Single-agent immunotherapy with the anti-PD-1 drug pembrolizumab has been approved by the FDA for the front-line treatment of patients with advanced EGFR/ALK wild-type NSCLC whose tumors have ≥50% tumor-cell PD-L1 expression using the 22C3 test (pharmDx; Dako North America). The gene discussed is CD274; the disease is non-small cell lung carcinoma.