CD274 and esophageal squamous cell carcinoma: Pembrolizumab significantly improved median OS compared to chemotherapy in patients with PD-L1 CPS ≥ 10 (9.3 months vs. 6.7 months, hazard ratio 0.69, p = 0.0074), and the subgroup of patients with the highest benefit was ESCC with PD-L1 CPS ≥ 10 (OS 10.3 months vs. 6.7 months, hazard ratio 0.64).