Subject has current central nervous system (CNS) or leptomeningeal metastases or history of CNS or leptomeningeal metastases. Leptomeningeal metastases Leptomeningeal metastases Known leptomeningeal or brainstem metastases. The presence of leptomeningeal enhancement alone, without associated clinical manifestations and/or positive CSF cytology, will not be constituted as known leptomeningeal metastases Active brain metastases or leptomeningeal metastases Leptomeningeal metastases Metastases detected below the tentorium or beyond the cranial vault, including tumors with evidence of leptomeningeal metastases as previously indicated; Presence of leptomeningeal metastases Diffuse Leptomeningeal metastases with radiographic involvement in the brain and/or spinal cord. This does not include local leptomeningeal involvement which is defined as leptomeningeal enhancement within direct contact of targetable metastases Participants must not have active brain metastases or leptomeningeal metastases Subjects with leptomeningeal metastases in lumbar area. History of leptomeningeal metastases Active leptomeningeal metastases Patients with leptomeningeal metastases Leptomeningeal metastases Must not have leptomeningeal metastases. Leptomeningeal metastases Participants in Part F must have HR+ breast cancer, NSCLC, or melanoma with leptomeningeal metastases. For Parts A, B, C, D, E: Have evidence of leptomeningeal metastases. Note: discrete dural metastases are permitted. Evidence of leptomeningeal metastases Participant has known leptomeningeal metastases. Patients with active brain metastases or leptomeningeal metastases Evidence of leptomeningeal metastases Active brain metastases or leptomeningeal metastases are not allowed. Active CNS metastases or leptomeningeal disease. Active brain metastases or leptomeningeal metastases Active brain metastases or leptomeningeal metastases CNS metastases or leptomeningeal disease requiring immediate treatment with radiation therapy or steroids. Subjects with active brain metastases or leptomeningeal metastases Patients with known or suspected leptomeningeal metastases. Known leptomeningeal metastases not amenable to radiotherapy; patients receiving radiotherapy for leptomeningeal metastases are eligible Brain metastases, leptomeningeal disease or bone metastases Known leptomeningeal metastases Active brain metastases or leptomeningeal metastases are not allowed History of leptomeningeal metastases Leptomeningeal metastases or brain metastases except as for Inclusion Criterion #6. Active brain metastases or leptomeningeal metastases Active metastases. Those with leptomeningeal metastases as the only site of CNS disease Patients with leptomeningeal metastases Symptomatic CNS metastases or evidence of leptomeningeal disease. Active metastases. Known brain metastases (unless asymptomatic and treated) or leptomeningeal metastases, including suspected leptomeningeal spread with positive cytology Active brain metastases or leptomeningeal metastases Presence of leptomeningeal disease or dural metastases. Leptomeningeal metastases, hemorrhagic metastases, presence of midline shift; please note: leptomeningeal metastases may be allowed if it is limited to cranial metastasis (magnetic resonance imaging [MRI] spine should be completed, within 4 weeks of enrollment, to show that no other leptomeningeal metastases is present) and is not the only metastasis present in the brain Evidence of CNS or leptomeningeal metastases History of leptomeningeal metastases Leptomeningeal metastases Leptomeningeal metastases Subjects with active brain metastases or leptomeningeal metastases Patients with definitive leptomeningeal metastases Leptomeningeal metastases; please note: leptomeningeal metastases may be allowed if it is limited to cranial metastasis (MRI spine should be completed, within 4 weeks of enrollment, to show that no other leptomeningeal metastases is present) and is not the only metastasis present in the brain History of leptomeningeal metastases Has active brain metastases or leptomeningeal metastases.