CD274 and small cell lung carcinoma: The previous study25 compared immunochemotherapy and chemotherapy in first‐line treatment of ES‐SCLC, but due to the lack of data and short‐term follow‐up, only four RCTs were included, the outcomes of PFS rate (6 months, 1 year), OS rate (1 year, 2 years), and subgroup analysis for PD‐L1 and LDH were not performed.