Inclusion Criteria:  Has rr DLBCL and has failed at least 2 lines of prior therapy and has failed auto- stem cell transplant (SCT) or are auto-SCT ineligible. Must have received prior rituximab/anti-CD20 (cluster of differentiation 20) monoclonal antibody. Has histologically confirmed diagnosis of DLBCL. Has radiographically measurable DLBCL per the Lugano Response Criteria. Should either be post- chimeric antigen receptor T cell therapy (CAR-T) failure or ineligible for CAR-T (for any reason). Life expectancy of at least 3 months. Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2 assessed within 7 days before time of enrollment. Has adequate organ function.  Exclusion Criteria:  Has received a diagnosis of Primary mediastinal B-cell lymphoma (PMBCL). Has undergone solid organ transplant at any time. Has a history of any clinically significant cardiovascular conditions within 6 months of screening or serious cardiac arrhythmia requiring medication. Has known history of liver cirrhosis. Has pericardial effusion or clinically significant pleural effusion. Has ongoing Grade >1 peripheral neuropathy. Has a history of a second malignancy, unless potentially curative treatment has been completed with no evidence of malignancy for 2 years. Transformed DLBCL from indolent lymphoma. In participants with prior allo-SCT, acute graft versus host disease (GVHD) or ongoing evidence of chronic GVHD. Has received prior systemic anticancer therapy, including investigational agents within 4 weeks prior to the first dose of study intervention. Has received prior radiotherapy within 4 weeks of start of study intervention. Participants must have recovered from all radiation-related toxicities, not require corticosteroids, and not have had radiation pneumonitis. Has ongoing corticosteroid therapy (exceeding 30 mg daily of prednisone equivalent). Has received a live or live-attenuated vaccine within 30 days before the first dose of study intervention. Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks before the first dose of study intervention. Has known active central nervous system (CNS) lymphoma involvement or active CNS involvement by lymphoma. Has an active infection requiring systemic therapy. Has a known history of human immunodeficiency virus (HIV) infection. Has a known history of hepatitis B or known active hepatitis C virus (HCV).