CD274 and esophageal squamous cell carcinoma: In the KEYNOTE-590 trial, patients with ESCC and esophageal adenocarcinoma with PD-L1 CPS ≥ 10 achieved better OS outcomes from the addition of pembrolizumab to cisplatin and 5-FU (HR, 0.62; 95% CI, 0.49–0.78) than those with PD-L1 CPS < 10 (HR, 0.86; 95% CI, 0.68–1.10)2.