In addition, according to previous studies on the use of PD1 inhibitors in neoadjuvant therapy for esophageal squamous cell carcinoma, there was no significant correlation between PD-L1 expression and pathological response (39, 40), so the determination of PD-L1 level in tumor tissue was not mandatory in our study design. This evidence concerns the gene PDCD1 and esophageal squamous cell carcinoma.