Absolute neutrophil count (ANC) >= ,/mcL within days prior to step randomization Absolute neutrophil count (ANC) >= ,/mcL within days prior to registration Within days prior to registration: Absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) >= ,/mcL within days prior to registration Absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) >= ,/mcl documented within days prior to step registration Absolute neutrophil count (ANC) >= /mcl within days prior to registration absolute neutrophil count (ANC) ?,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL SAFETY RUN-IN: Within days of registration: Absolute neutrophil count (ANC) >= , /mcL RANDOMIZED PHASE II CLINICAL TRIAL: Within days of registration: Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) < ,/mcL Absolute neutrophil count (ANC) >= ,/mcL. Within days of treatment registration: Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) > /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC): >= /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= /mcL; a subject will not be excluded because of pancytopenia related to disease Absolute neutrophil count (ANC) >= ,/mcL Within days of cycle day : Absolute neutrophil count (ANC)\t>= ,/mcL Within days prior to the start of study treatment: Absolute neutrophil count (ANC) >= , /mcL. Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= , /mcL. Absolute neutrophil count (ANC) >= . k/mcl, obtained within days prior to first study treatment Absolute neutrophil count (ANC) >= , /mcL. Within days of registration: Absolute neutrophil count (ANC) >= ,/mcL Within days prior to on-study date: Absolute neutrophil count (ANC) ? ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= /mcL Absolute neutrophil count (ANC) ? ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/ mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Obtained within days prior to enrollment: absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) > /mcL Absolute neutrophil count (ANC) >= /mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL. Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL, during screening and on cycle , day Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC): >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL within days prior to registration Absolute neutrophil count (ANC) > /mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) < /mcl Absolute neutrophil count (ANC) >= ,/mcL PHASE I: Absolute neutrophil count (ANC) > ,/mcl PHASE II: Absolute neutrophil count (ANC) > ,/mcl Absolute neutrophil count (ANC) >= ,/mcL except in cases of marrow infiltration by lymphoma Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Newly diagnosed MCL: Absolute neutrophil count (ANC) > /mm^; patients who have bone marrow infiltration by MCL are eligible if their ANC is equal to or > than Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) < /mcL Patients must have absolute neutrophil count (ANC) > /mcl Absolute neutrophil count (ANC) ? ,/mcL OR ? /mcL if neutropenia due to iBCL Absolute neutrophil count (ANC) >= , /mcL Within days prior to registration: Absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) >= , /mcL REGISTRATION TO TREATMENT (STEP ): Absolute neutrophil count (ANC) >= , /mcL, within days prior to first dose of pembrolizumab REGISTRATION TO TREATMENT (STEP ): Absolute neutrophil count (ANC) >= , /mcL, within days prior to first dose of pembrolizumab Absolute neutrophil count (ANC) >= /mcL Absolute neutrophil count (ANC) ? ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >=, /mcL Absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= , /mcL Within days of registration: Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , cells/mcL within days prior to registration Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) < . K/mcL at time of enrollment Absolute neutrophil count (ANC) >= ,/mcL Within days prior to registration: Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= /mcL Absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= /mcl (filgrastim [G-CSF] is allowed) (must be within days of MLA) Absolute neutrophil count (ANC) > /mcL Absolute neutrophil count (ANC) >= . K/mcL Absolute neutrophil count (ANC) > /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= /mcL Absolute Neutrophil Count (ANC) ? ,/mcL Absolute neutrophil count (ANC) of at least per mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) < /mcl An absolute neutrophil count (ANC) >= ,/mcl Absolute neutrophil count (ANC) > /mcl Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) > cells/mcl Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) < . K/mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= ,/mcL within days prior to registration Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= /mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) < . K/mcL At the discretion of the operating surgeon, absolute neutrophil count (ANC) > /mcl Absolute neutrophil count (ANC) < . K/mcL At the discretion of the physician, absolute neutrophil count (ANC) > /mcl Absolute neutrophil count (ANC) < . K/mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= , /mcL Absolute neutrophil count (ANC) >= ,/mcL Absolute neutrophil count (ANC) >= , /mcL