CD274 and neoplasm: Some patients with PD-L1-negative cancer (epithelial signature), across a wide variety of human cancer types, also show robust responses to PD-1/PD-L1 antibodies (e.g., nivolumab), suggesting that PD-L1 overexpression in tumor tissues is neither a sufficient nor necessary condition for guaranteeing improved clinical benefits (survival time) for patients.343–349