Boussios et al. showed that diffuse PD-L1 expression in squamous cell carcinoma is correlated with poor disease-free survival and disease-specific survival compared to the cases with marginal PD-L1 expression; in adenocarcinoma, survival benefit was observed for the patients with tumors lacking PD-L1-positive tumor-associated macrophages [28,29]. This evidence concerns the gene CD274 and squamous cell carcinoma.