Lung cancer is the leading cause of cancer-related mortality worldwide.1 Immune checkpoint inhibitors (ICIs), which target programmed cell death protein 1 (PD-1) and its ligand (PD-L1) or cytotoxic T lymphocyte antigen-4 (CTLA-4) can elicit durable antitumor responses in multiple cancer types, including non-small-cell lung cancer (NSCLC).2–5 Yet, only a minority of patients with advanced NSCLC derive clinical benefit from this treatment.6 Therefore, there is an urgent need to investigate the predictive biomarkers for ICIs treatment effectiveness. This evidence concerns the gene CD274 and cancer.