PDCD1 and head and neck squamous cell carcinoma: Moreover, the results of some phase 1/2 studies (NCT02621398, NCT02434081, NCT02586207, NCT02383212, and NCT02402920) showed that α-PD-1/PD-L1 plus chemoradiotherapy was tolerable in advanced NSCLC, head and neck squamous cell carcinoma (HNSCC), and SCLC patients, with promising clinical outcomes [78–82].