We further found that cytotoxicity scores of CD8+ TEFF increased significantly after anti-PD-1 therapy in HBV+ ESCC patients, with HBV+#2 showing the most pronounced increase, while cytotoxicity scores of CD8+ TEFF significantly decreased in HBV–#1 (Fig. 3A). This evidence concerns the gene PDCD1 and esophageal squamous cell carcinoma.