CD274 and esophageal squamous cell carcinoma: In the past decade, a handful of targeted therapies have been approved for EC, including trastuzumab combined with chemotherapy as the first-line treatment for HER2-positive esophageal adenocarcinoma [3], the vascular endothelial growth factor (VEGF) receptor inhibitor ramucirumab as the second-line treatment for gastric or gastro-esophageal junction adenocarcinoma [4, 5], and pembrolizumab for the treatment of PD-L1-positive ESCC or EAC [6].