US FDA approval of atezolizumab (an anti‐PD‐L1 antibody) in combination with platinum‐based chemotherapy for the first‐line treatment of ES‐SCLC was an important milestone.[12] Subsequently, a combination of durvalumab (an anti‐PD‐L1 antibody) and chemotherapy entered phase 3 trials and was found to similarly improve the OS of the patients.[32] Unfortunately, however, CheckMate trials 331 and 451 of nivolumab (an anti‐PD1 antibody) did not show positive results.[33] The results of these trials stimulated our intense curiosity about immune infiltration in the TME of SCLC. The gene discussed is PDCD1; the disease is small cell lung carcinoma.