CD274 and esophageal squamous cell carcinoma: The estimated 24-month OS rate in the pembrolizumab–chemotherapy group versus placebo–chemotherapy group was 41.9% versus 34.3% in all randomly assigned patients, 43.3% versus 33.9% in patients with ESCC, 39.6% versus 22.2% in patients with PD-L1 CPS ≥ 10, and 38.6% versus 18.8% in patients with ESCC PD-L1 CPS ≥ 10.