CD274 and esophageal squamous cell carcinoma: Phase III trials consistently demonstrated that combining anti‐PD‐1/PD‐L1 antibodies with conventional chemotherapy as a first‐line treatment for unresectable, locally advanced, recurrent, or metastatic ESCC significantly improved treatment efficacy and prognosis compared to chemotherapy alone, with an absolute increase in objective response rate (ORR) from 10.0% to 21.1% and an extension in median overall survival (mOS) by 2.8–6.6 months [10, 11, 12, 13, 14, 15, 16, 17].