In phase III clinical trials, ESCC patients who progressed after one prior therapy with the PD-1 inhibitor, pembrolizumab, showed improved overall survival (OS) to a median OS of 8.2 months, compared with 7.1 months in patients who received chemotherapy (KEYNOTE-181) [10]. The gene discussed is PDCD1; the disease is esophageal squamous cell carcinoma.