Over the past few years, several clinical trials have evaluated the efficacy of checkpoint inhibitors [mainly cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and programmed death 1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors] in SCLC patients and demonstrated promising survival prospects. The gene discussed is CTLA4; the disease is small cell lung carcinoma.