Inclusion Criteria: - Pathologically confirmed high-risk recurrent/relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL), after non-response to or failure of first-line standard therapy prior to a definitive therapy e.g.high-dose chemotherapy/autologous stem cell transplant (HDCT/ASCT) - Participants with pathologically confirmed R/R NHL after failure or non-response to second line therapy, including but not limited to primary mediastinal B-cell lymphoma, diffuse large B-cell lymphoma (DLBCL), mediastinal gray zone lymphoma (MGZL), anaplastic large cell lymphoma (ALCL), or peripheral T-cell lymphoma (PTCL). - Participants must have measurable PET positive disease in both cHL and NHL cohorts. Exclusion Criteria: - Aggressive B-cell lymphomas subtypes including Burkitt lymphoma (BL), lymphoblastic lymphoma, and NK/T-cell lymphoma/leukemia. - Primary CNS lymphoma of the brain or spinal cord, and secondary CNS lymphoma (ie, from systemic non-Hodgkin lymphoma) involving the brain, spinal cord, or with leptomeningeal seeding. - Prior treatment with an anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4) antibody, or any other antibody or drug specifically targeting T-cell co-stimulation or checkpoint pathways, with the exception of anti-PD(L)-1 targeted therapies - Prior treatment with lymphocyte activation gene-3 (LAG-3)-targeted agents - Prior autologous stem cell transplantation (HDCT/ASCT) - History of allogeneic bone marrow transplantation. Other protocol-defined inclusion/exclusion criteria apply