Currently, the A2AR clinical trials are focused on three main points: (1) monotherapy and combination with anti-PD-L1 antibodies showed complete and prolonged inhibition of A2AR, which is well tolerated in cancer patients; (2) A2AR antagonists elicit antitumor immunity from monotherapy and in the combination with anti-PD-L1, and (3) different pools of patients need to be identified based on the predictive biomarkers of adenosine pathway blockade [215]. The gene discussed is ADORA2A; the disease is cancer.