CD274 and small cell lung carcinoma: IMpower133 and CASPIAN firstly demonstrated the efficacy of PD-L1 inhibitors combined with chemotherapy, followed by CAPSTONE-1 and PD-1 inhibitors in SCLC demonstrated by ASTRUM-005, RATIONALE-312, and EXTENTORCH, to the innovative four-drug model of ETER701, which further refreshed the OS survival of first-line treatment of ES-SCLC to 19.3 months (17).