PDCD1 and esophageal squamous cell carcinoma: In a phase-II study of chemotherapy plus PD-1 for resectable ESCC, patients were given toripalimab plus paclitaxel and cis-platinum prior to surgery for two cycles, the results exhibited that the R0 resection rate was 100%, and 33.3% patients achieved pCR (Liu et al., 2021).