IL4I1 and cancer: Indeed, we found that the expression of IL4I1 shows positive associations with the abundance of Treg cells (Spearman correlation test: R = 0.611, P = 1.55e−29), myeloid derived suppressor cells (R = 0.811, P < 2.e−16) and exhausted T cell (R = 0.75, P = 0) and negative association with tumor purity (R = -0.361, P = 5.75e−14; Fig. 4C), indicated its immunosuppressive effects and promising target for CRC cancer immunotherapy.