A Study to Evaluate Adverse Events and Change in Disease Activity of Subcutaneous (SC) Epcoritamab in Combination With Oral and Intravenous Anti-Neoplastic Agents in Adult Participants With Non-Hodgkin Lymphoma

Inclusion Criteria: * Diagnosis of: \-- Diffuse large B-cell lymphoma (DLBCL) (de novo or histologically transformed from follicular lymphoma (FL) or nodal marginal zone lymphoma) with histologically confirmed CD20+ disease, inclusive of the following according to World Health Organization (WHO) 2016 classification and documented in pathology report: * DLBCL, not otherwise specified (NOS). * High-grade B cell lymphoma with MYC and BCL-2 and/or BCL-6 translocations per WHO 2016 ("double-hit" or "triple-hit") Note: High-grade B-cell lymphomas NOS or other double- /triple-hit lymphomas (with histologies not consistent with DLBCL) are not eligible. * Follicular lymphoma (FL) Grade 3B. OR * FL with histologically confirmed CD20+ Grade 1 to 3a and no evidence of histologic transformation to an aggressive lymphoma at most recent representative tumor biopsy, according to WHO 2016 classification. OR * Mantle cell lymphoma (MCL) with histologically confirmed CD20+ disease at most recent representative tumor biopsy according to the WHO 2016 classification with evidence of overexpression of cyclin D1 in association with relevant markers or evidence of t(11;14) assessed by flow cytometry, fluorescence in situ hybridization (FISH), or polymerase chain reaction (PCR). * Eastern Cooperative Oncology Group (ECOG) performance status 0 - 2, except for Arm 6A where ECOG performance status must be 0-1. * Must have 1 or more measurable disease sites: * A positron emission tomography (PET) /computed tomography (CT) scan demonstrating PET-positive lesion(s) AND * At least 1 measurable nodal lesion (long axis \> 1.5 cm) or \>= 1 measurable extra-nodal lesion (long axis \> 1.0 cm) on CT scan or magnetic resonance imaging (MRI). Exclusion Criteria: * Prior treatment with epcoritamab or any other bispecific antibody targeting CD3 and CD20. * Toxicities from prior anticancer therapy that have not resolved to Common Terminology Criteria for Adverse Events (CTCAE, v 5.0), Grade 2 or below, with the exception of alopecia. Other eligibility criteria (e.g., laboratory, cardiac criteria) must also be met.