CD274 and head and neck squamous cell carcinoma: Of the 24 patients with HNSCC previously treated with anti-PD-1/PD-L1 agents, 19 were evaluable for response and, among these, there were no responses, although 9 (47%) patients experienced disease stabilization, with a median duration of disease control of 3.55 months (range, 2.00–8.05).