The prognostic value of PD-1 was largely undefined in NPC, one possible illustration might be that PD-1 expression in TILs was usually dynamically changed according to the immune status [32], and the prognostic role of PD-1 in recurrent NPC as well as in primary tumors still needs to be further clarified. This evidence concerns the gene PDCD1 and nasopharyngeal carcinoma.