In patients with ES‐SCLC without LM, CIT was superior to CT alone in both the anti‐PD‐1 and anti‐PD‐L1 subgroups (HR for PFS, 0.53; 95% CI, 0.47%–0.59%; p < 0.001; HR for OS, 0.69; 95% CI, 0.63%–0.76%; p < 0.001; Figure 3A,B). This evidence concerns the gene PDCD1 and small cell lung carcinoma.