A Study of Zilovertamab Vedotin (MK-2140) in Combination With Standard of Care in Participants With Relapsed or Refractory Diffuse Large B-Cell Lymphoma (rrDLBCL) (MK-2140-003)

Inclusion Criteria: * Has a histologically confirmed diagnosis of Diffuse Large B-Cell Lymphoma (DLBCL). * Has radiographically measurable DLBCL per the Lugano Response Criteria, as assessed locally by the investigator. * Has an Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 to 2 within 7 days prior to study treatment initiation. * Has adequate organ function. * Is able to provide new or archival tumor tissue sample not previously irradiated. Zilovertamab vedotin plus R-GemOx, or R-GemOx study arms: * Has relapsed or refractory DLBCL and is ineligible for or have failed autologous stem-cell transplant (ASCT) and have failed at least 1 line of prior therapy. * Has post-chimeric antigen receptor T (post-CAR-T) cell therapy failure or is ineligible for CAR-T cell therapy. Not applicable with protocol amendment 4: Zilovertamab vedotin plus Bendamustine Rituximab (BR), and Bendamustine Rituximab study arms: * Has relapsed or refractory DLBCL and is ineligible for or have failed ASCT and have failed at least 2 lines of prior therapy. * Has post-CAR-T therapy failure or is ineligible for CAR-T cell therapy. Exclusion Criteria: * Not applicable with protocol amendment 4: Has history of transformation of indolent disease to DLBCL * Has received solid organ transplant at any time. * Has received a diagnosis of primary mediastinal B-cell lymphoma (PMBCL). * Has clinically significant (ie, active) cardiovascular disease or serious cardiac arrhythmia requiring me…