Pembrolizumab (KeytrudaTM, Merck & Co., Inc., Rahway, NJ, USA) and nivolumab (OPDIVOTM, Bristol-Myers Squibb Company, New York, NY, USA), two humanized monoclonal antibodies against PD-1, have been approved in HNSCC treatment by the U.S. Food and Drug Administration (FDA) and the European Medical Agency (EMA) [8]. Here, PDCD1 is linked to head and neck squamous cell carcinoma.