IDO1 and cancer: As expected, we observed upregulation of known inhibitory immune checkpoints (CD274, IDO1, KDR, and transforming growth factor beta receptor I), markers of progressive CD8+T cell exhaustion (HAVCR2, ENTPD1, TIGIT, TNFRSF9, LAYN, PHLDA1, and SNAP47), and CD4+Th2/Th1, all of which demonstrated that RIOK2 might be a potential therapeutic target governing key hallmarks of immune suppression in various cancer types.