The introduction of PD-L1-based companion and complementary diagnostic assays has greatly increased the efficacy and safety of anti-PD-1/PD-L1 therapy in selected patients, suggesting that the PD-L1 is one of the predictive biomarkers for PD-1/PD-L1 inhibitors in NSCLC. The gene discussed is CD274; the disease is non-small cell lung carcinoma.