Abstract: Adenosine 2a receptor (A2aR) is a type of G-protein coupled receptor widely existing on the surface of various immune cells, and plays important role in the regulation of host immune functions through its binding with adenosine(ADO). Here we summarize the significance of A2aR in promoting the immune-suppressive status in tumor microenvironment, and provide evidence for the clinical application of treatment interfering with A2aR.