The NCT01938612 is a phase I clinical trial to evaluate the safety, tolerability, and antitumor activity of durvalumab monotherapy, and durvalumab plus tremelimumab (anti-CTLA-4 monoclonal antibody) combination therapy in patients from Asia with ESCC as second-line and beyond treatment, which showed that both treatments displayed acceptable safety profiles clinical benefit (184). This evidence concerns the gene CTLA4 and esophageal squamous cell carcinoma.