A Study to Assess the Safety and Tolerability of BMS-986525 Alone and in Combination With Nivolumab in Participants With Relapsed/Refractory Small Cell Lung Cancer

This early-phase study is testing a new drug called BMS-986525, alone and in combination with nivolumab (an immunotherapy), for people with small cell lung cancer (SCLC) that has relapsed (come back) or stopped responding to prior treatment. SCLC is an aggressive form of lung cancer, and new options are urgently needed. **You may be eligible if...** - You have been confirmed to have relapsed or refractory small cell lung cancer (by biopsy or pathology) - You have received at least one platinum-based chemotherapy regimen - If the standard of care in your country includes immunotherapy with chemotherapy, you must have already received that or been ineligible for it **You may NOT be eligible if...** - You have untreated brain metastases (brain tumors that haven't been treated) - You have an active autoimmune disease - You have had an organ or tissue transplant from another person Talk to your doctor to see if this trial is right for you.