There are a number of studies in the literature highlighting that PD-1, PD-L1 and A2aR intrinsic signalling in tumour cells also promote tumour cell proliferation in a range of cancer types including hepatocellular carcinoma19, lung, melanoma20, ovarian20, pancreatic64, gastric15,16,65 and cervical cancer16. This evidence concerns the gene ADORA2A and cancer.