CD274 and esophageal squamous cell carcinoma: In the ESCC PD-L1 CPS ≥ 10 subgroup, 27 of 44 patients (61.4%) receiving pembrolizumab–chemotherapy and 26 of 32 patients (81.3%) receiving placebo–chemotherapy died (Fig. 1d); median OS (95% CI) was 15.8 months (12.8–NE) and 10.9 months (7.8–14.6), respectively (HR, 0.55; 95% CI 0.32–0.94).