CD274 and cancer: Fuse et al. (2016) reported that PD-L1 blockade decreased the immune suppression ability of MDSCs on T cells. Moreover, recent studies have found that MDSCs mediate their suppression on T cells through adenosine. MDSCs from tumor tissues of patients with cancer increased adenosine production through considerable upregulation of CD39 and CD73 in vitro, and adenosine signals mainly through A2A type and A3 type adenosine receptors to suppress T cell activation and immune response (Umansky et al., 2014; Li et al., 2018).