Diagnosis of immunodeficiency or is receiving treatment with systemic steroid therapy or any other form of immunosuppressive therapy within seven days prior to registration for protocol therapy Has a diagnosis of immunodeficiency, is receiving systemic steroid therapy (except for physiological dose levels), or immunosuppressive therapies Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of AMG 757 SAFETY RUN-IN: Diagnosis of immunosuppression or receiving steroid therapy or other immunosuppressive therapy within 4 weeks of the study RANDOMIZED PHASE II CLINICAL TRIAL: Diagnosis of immunosuppression or receiving steroid therapy or other immunosuppressive therapy within 4 weeks of the study Diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study treatment. Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior the first dose of study therapy Any systemic steroid therapy or other form of immunosuppressive therapy within 7 days of the first dose of mRNA-4157 or pembrolizumab Is receiving systemic steroid therapy ?7 days prior to the first dose of study therapy or receiving any other form of immunosuppressive medication Any diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 14 days of initiation of therapy Patients who have a diagnosis of immunodeficiency or are receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to registration are not eligible Must not have a diagnosis of immunodeficiency, or receiving systemic steroid therapy, or any other form of immunosuppressive therapy within 7 days prior to trial treatment; short burst of steroids of 5-7 days (for chronic obstructive pulmonary disease [COPD] exacerbation or other similar indication) are allowed Diagnosis of immunodeficiency or is receiving systemic steroid therapy (other than oral contraceptives) or any other form of immunosuppressive therapy within 7 days prior to registration Diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to study registration. Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the date of allocation/randomization Patient has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of pembrolizumab Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of HiDAC treatment; NOTE: use of steroid eye drops starting at the time of HiDAC administration is allowed Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug. Has a known diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to study registration Systemic steroid therapy or any other form of immunosuppressive therapy within 14 days prior to registration Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 14 days prior to the first dose of the study drug Any diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 14 days of initiation of therapy Receiving systemic steroid therapy or any form of immunosuppressive therapy within 1 week prior to the start of study drug Any diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 14 days of initiation of therapy Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study treatment. Has a diagnosis of immunodeficiency, or is receiving systemic steroid therapy above physiologic replacement dose, or any other form of immunosuppressive therapy Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to on-study date Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy =< 7 days prior to registration Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study treatment. Diagnosis of immunosuppression or receiving steroid therapy or other immunosuppressive therapy within 4 weeks of the study Diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of trial treatment\r\n* Short-term administration of systemic steroids (i.e., for allergic reactions or the management of immune related adverse events [irAEs]) is allowed Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to registration Has a diagnosis of immunodeficiency or any other form of immunosuppressive therapy. Is receiving systemic steroid therapy within three days prior to the first dose of trial treatment or receiving any other form of immunosuppressive medication (corticosteroid use on study for management of early combined immunosuppression [ECIs] is allowed) Subjects who have a diagnosis of immunodeficiency or are receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study treatment Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the initiation of SBRT Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to study drug administration Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of trial treatment; the use of physiologic doses of corticosteroids for adrenal and pituitary insufficiency is not considered a form of systemic steroid therapy and would not exclude a subject from the study Has a diagnosis of immunodeficiency or is receiving systemic immunosuppressive therapy within 7 days of study entrance Has a known history of immunosuppression or is receiving systemic steroid therapy or any other form of systemic immunosuppressive therapy within 7 days Subject has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to enrollment Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy Patient has a diagnosis of immunodeficiency or is receiving ongoing immunosuppressive therapy, including systemic or enteric corticosteroids except for non-systemically absorbed treatments (such as inhaled or topical steroid therapy for asthma, chronic obstructive pulmonary disease, allergic rhinitis). Patient must be off systemic steroid or any other form of immunosuppressive therapy within 7 days prior to first dose of trial treatment Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 2 weeks prior to randomization REGISTRATION TO TREATMENT (STEP 1): Patient must not have a diagnosis of immunodeficiency or be receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of treatment REGISTRATION TO TREATMENT (STEP 2): Patient must not have a diagnosis of immunodeficiency or be receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of treatment Has received systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to registration for protocol therapy Diagnosis of immunodeficiency or be receiving systemic steroid therapy or any other form of immunosuppressive therapy =< 7 days prior to registration Any diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 14 days of initiation of therapy Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 2 weeks of the first protocol treatment; the use of low-dose steroids for management of chronic conditions is allowed Has a diagnosis of immunodeficiency or is receiving systemic immunosuppressive steroid therapy or any other form of systemic immunosuppressive therapy within 7 days prior to the first dose of trial treatment; exception: physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency is not considered systemic immunosuppressive steroid therapy Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to randomization on this study Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug. Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to treatment allocation Is receiving systemic steroid therapy <3 days before the first dose of study drug or receiving any other form of immunosuppressive medication. Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to randomization. Immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study treatment Diagnosed with immunodeficiency or receiving systemic steroid therapy or another form of immunosuppressive therapy within 7 days Receiving TNF pathway inhibitors, PI3 kinase inhibitors, systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug Has a diagnosis of immunodeficiency OR is receiving a systemic steroid therapy exceeding physiologic corticosteroid dose or any other form of immunosuppressive therapy within 7 days prior to randomization, except in the case of central nervous system (CNS) metastases. Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug Receiving TNF pathway inhibitors, PI3 kinase inhibitors, systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the planned first dose of the study Receiving systemic steroid therapy <= 3 days prior to first dose of study drug or receiving any other form of immunosuppressive medication Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug Receiving systemic steroid therapy within 3 days prior to the first dose of study treatment or receiving any other form of immunosuppressive medication Within 7 days prior to the planned start of study treatment:\r\n* Is receiving systemic steroid therapy or any other form of immunosuppressive therapy Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of trial treatment, exceptions include topical, intralesional, intraarticular and inhaled steroids; a pulse steroid dose prior to and after imaging to prevent contrast allergy in patients with known allergy to contrast is allowed Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication Diagnosis of immunosuppression or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication Systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication Diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to study registration. Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the radiation therapy Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study therapy Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to randomization Subject is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 2 weeks prior to first dose of study treatment. Has a diagnosis of immunodeficiency or is receiving any form of immunosuppressive therapy within 7 days prior to the first dose of study treatment Systemic steroids, any other form of immunosuppressive therapy or radiation therapy within 14 days prior to registration. Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy. Diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to enrollment. Diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy (including immune modulators or systemic corticosteroids) within 7 days prior to study enrollment. Known diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study treatment Known diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study treatment Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to day 1 Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study therapy Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study treatment Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to C11-AMT PET scan Diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy =< 7 days prior to registration Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to randomization. Has a diagnosis of immunosuppression or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug.