Study to Compare Axicabtagene Ciloleucel With Standard of Care Therapy as First-line Treatment in Participants With High-risk Large B-cell Lymphoma

Key Inclusion Criteria: * Histologically confirmed large B cell lymphoma (LBCL) based on 2016 World Health Organization (WHO) classification by local pathology lab assessment, including of the following: * Diffuse large B-cell lymphoma (DLBCL), not otherwise specified (NOS) * High-grade B-cell lymphoma (HGBL) * Note: Transformed DLBCL from follicular lymphoma or from marginal zone lymphoma is eligible if no prior treatment with anthracycline-containing regimen. * High-risk disease defined as an International Prognostic Index (IPI) score of 4 or 5 at initial diagnosis. * Have received only 1 cycle of rituximab plus chemotherapy (R-chemotherapy). * Adequate bone marrow, renal, hepatic, pulmonary, and cardiac function. * Females of childbearing potential must have a negative serum or urine pregnancy test. Key Exclusion Criteria: * The following WHO 2016 subcategories by local assessment: * T-cell/histiocyte-rich LBCL * Primary DLBCL of the central nervous system (CNS) * Primary mediastinal (thymic) LBCL * B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and classical Hodgkin lymphoma * Burkitt lymphoma * History of Richter's transformation of chronic lymphocytic leukemia * Presence of detectable cerebrospinal fluid (CSF)-malignant cells, brain metastases, or a history of CNS involvement of lymphoma. * Presence of cardiac lymphoma involvement. * Any prior treatment for LBCL other than the 1 cycle of R-chemotherapy. * History of severe…