In recent years, immune checkpoint inhibitors (ICIs), including programmed death 1 (PD‐1) and programmed death ligand 1 (PD‐L1) inhibitors, have shown remarkable progress in improving the prognosis of patients with ES‐SCLC by restoring T‐lymphocyte function in antitumor immunity. The gene discussed is PDCD1; the disease is small cell lung carcinoma.