CD274 and esophageal squamous cell carcinoma: Regarding the responses, pembrolizumab improved the ORR in the PD-L1 ≥ 10 (regardless of the histology, 21.5% versus 6.1%) and ESCC subgroups (16.7 versus 7.4%), whereas no benefit in responses was showed in PD-L1 < 10 subgroup.