The purpose of this study is to assess the safety and tolerability of BMS-986525 alone and in combination with Pumitamig in participants with Relapsed/Refractory Small Cell Lung Cancer
Participants must have histologically or cytologically documented relapsed/refractory small cell lung cancer (R/R-SCLC).
Participants must have received at least 1 platinum-based chemotherapy regimen as per locally approved drug labels and institutional guidelines.
In countries where standard of care first line systemic treatment includes platinum containing chemotherapy in combination with anti-PD-(L)1 therapy, it is required that participants have progressed on, are ineligible for or not have access to an anti-PD- (L)1 therapy.
Participants must not have any untreated CNS metastases.
Participants must not have an active, known or suspected autoimmune disease.
Participants must not have had a prior organ or tissue allograft.
Other protocol-defined Inclusion/Exclusion criteria apply.