A Study to Evaluate Safety, Drug Levels and Effectiveness of CC-92480 (BMS-986348) in Combination With Other Treatments in Participants With Relapsed or Refractory Multiple Myeloma

Inclusion Criteria: * Relapsed or refractory multiple myeloma (MM) and must: 1. Have documented disease progression during or after their last myeloma therapy. 2. For Part 1 Dose Finding: Be refractory to, intolerant to, or not a candidate for available, established therapies known to provide clinical benefit in MM; For Part 2 Dose Expansion: Be refractory to or have relapsed after the protocol specified number of prior lines of therapy that include an immunomodulatory drug (IMiD), a proteasome inhibitor, an anti-CD38 mAb, and a T-cell redirecting therapy (TRT, eg, a CAR-T or T-cell engaging bispecific treatment) unless the participant is not a candidate for TRT. * Must have measurable disease. * Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 or 1. * Agree to follow the CC-92480 Pregnancy Prevention Plan (PPP). Exclusion Criteria: * Known active or history of central nervous system (CNS) involvement of MM * Plasma cell leukemia; Waldenstrom's macroglobulinemia; polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS) syndrome; or clinically significant light-chain amyloidosis. * Impaired cardiac function or clinically significant cardiac disease * Previous SARS-CoV-2 infection within 14 days for asymptomatic or mild symptomatic infections or 28 days for severe/critical illness prior to Cycle 1 Day 1 (C1D1) * For Part 1: received prior therapy with CC-92480 * For Part 2: received prior therapy with CC-92480, tazemetostat, BMS-986158, or trametinib * Previously received allogeneic stem-cell transplant at any time or received autologous stem-cell transplant within 12 weeks of initiating study treatment * Received any of the following within 14 days prior to initiating study treatment: 1. Plasmapheresis 2. Major surgery 3. Radiation therapy other than local therapy for myeloma associated bone lesions 4. Use of any systemic anti-myeloma drug therapy * Used any investigational agents within 28 days or 5 half-lives (whichever is shorter) prior to initiating study treatment * COVID-19 vaccine within 14 days prior to C1D1 Other protocol-defined inclusion/exclusion criteria apply