Specifically, immunotherapy targeting programmed cell death-1 (PD-1) and programmed death-ligand 1 (PD-L1) has considerably improved the overall survival of patients, not only in those with metastatic NSCLC, but also in patients with locally advanced disease and extensive-stage small-cell lung cancer [4,14,15,16,17,18,19,20,21]. The gene discussed is PDCD1; the disease is small cell lung carcinoma.