Similarly, in the first‐line treatment of ES‐SCLC, the comparison of efficacy and safety between PD‐1 inhibitors combined with chemotherapy and PD‐L1 inhibitors combined with chemotherapy is also controversial, and considering that direct head‐to‐head comparisons of PD‐1 inhibitors with chemotherapy and PD‐L1 inhibitors with chemotherapy RCTs in the first‐line treatment of ES‐SCLC are highly improbable, a number of systematic reviews and NMA were conducted by indirect comparison. This evidence concerns the gene PDCD1 and small cell lung carcinoma.