PDCD1 and head and neck squamous cell carcinoma: Following the promising results of the open-label, multicenter, phase 1b trial KEYNOTE-012, the PD-1 antibody received approval via accelerated process for patients with recurrent and/or metastatic HNSCC (R/M HNSCC) as a second-line treatment option after progression on standard platinum-based therapy (9, 10).