Blocking the PD-1/PD-L1 signaling pathway with drugs or monoclonal antibodies has emerged as a novel cancer immunotherapy strategy, demonstrating efficacy in treating various types of cancers, including malignant melanoma, non-small cell lung cancer, renal cell carcinoma, squamous cell carcinoma and gastric cancer (1, 2). The gene discussed is PDCD1; the disease is non-small cell lung carcinoma.