CD274 and small cell lung carcinoma: The KEYNOTE-158 trial, a phase II basket study of 11 cancer types, observed that pembrolizumab exhibited superior antitumor effects and sustained responses in ES-SCLC patients with PD-L1 CPS ≥ 1 compared to those who were PD-L1 negative, indicating that PD-L1 CPS could predict outcomes in ES-SCLC patients [42].