CD8A and esophageal squamous cell carcinoma: Therefore, it is necessary to treat them with the optimal medical treatments; from this study, salvage surgery should be considered for ESCC with a low ratio of PD-L1/CD8 after definitive CRT, while a PD-1/PD-L1 blockade should be recommended for those with a high ratio of PD-L1/CD8 [30].