PD1/PDL1 therapy currently is also in phase III clinical trials for the indications of BRAF V600-mutated melanoma [51], RCC [18, 30], head and neck squamous cell carcinoma (HNSCC) [31, 52], nasopharyngeal cancer [53], esophageal carcinoma [54], mesothelioma [55], hepatocellular carcinoma [48], breast cancer [20], and multiple myeloma [4]. Here, PDCD1 is linked to head and neck squamous cell carcinoma.