Epcoritamab and Lenalidomide in Treating Patients With Refractory or Relapsed Immunodeficiency-Related Large B-Cell Lymphoma

Inclusion Criteria: * Patients must have a pathologically confirmed diagnosis of immunodeficiency-related large B-cell lymphoma as defined by the 5th Edition of the World Health Organization (WHO) Classification of Hematolymphoid Tumors 2022 in addition to any of the following: * Lymphomas arising in immune deficiency which encompass monomorphic post-transplant lymphoproliferative disorder (PTLD) OR * Polymorphic B-cell lymphoproliferative disorder arising in the setting of immunodeficiency and/or immune dysregulation as seen in 1 or more of the following settings: * Underlying autoimmune disease * Iatrogenic or therapy-related immunosuppression * Conditions arising from inborn errors of immunity * Immune senescence as seen in patients aged ≥80 years or those ≥ 65 years with CD4 count \< 500 cells/mm\^3 * Epstein-Barr virus (EBV) infection as demonstrated by EBV positivity in the tumor cells * Patients must have measurable disease (≥ 1 measurable nodal lesion \[long axis \> 1.5 cm\] or ≥ 1 measurable extra-nodal lesion \[long axis \> 1.0 cm\] on CT scan or MRI) per Lugano criteria * Note; Patients with hepatomegaly /organomegaly deemed to be related to disease will also be eligible if not meeting strict Lugano criteria * Patients must meet one disease status as follows AND deemed ineligible for chimeric antigen receptor T-cell (CAR-T): * Primary refractoriness defined as a partial response or less on interim PET-CT during therapy with frontline chemo-imm…