Second, to define the PD-L1 positive subgroup, we included patients with a PD-L1 CPS score ≥ 1; however, a subgroup analysis of Checkmate-648 study has shown that tumor cell PD-L1 expression, very similar to TPS, also has clinical utility in ESCC. The gene discussed is CD274; the disease is esophageal squamous cell carcinoma.