A phase I clinical trial (NCT02655822) of A2AR antagonist (PBF-509 and CPI-444) alone or with immune checkpoint inhibitor (atezolizumab, a PD-L1 inhibitor) is currently recruiting participants to study the clinical efficiency of A2AR blockade for solid tumor including HNSCC. This evidence concerns the gene CD274 and head and neck squamous cell carcinoma.