CD274 and small cell lung carcinoma: While anti-PD-1/PD-L1-based immunochemotherapy strategies have improved survival outcomes, achieving response rates of 80%–90% in limited-stage SCLC (LS-SCLC) and 50%–80% in extensive-stage SCLC (ES-SCLC) (Schmittel, 2011), this approach remains restricted to first-line settings.