Recently, with the promising efficacy of anti-programmed cell death-1/ligand-1 (PD-1/PD-L1) inhibitor in melanoma, NSCLC, renal cell cancer, and other solid tumors, a variety of clinical trials have been performed to estimate the antitumor performance of immunotherapy in SCLC (6). The gene discussed is PDCD1; the disease is small cell lung carcinoma.