Mammalian target of rapamycin (mTOR) is a serine/threonine (Thr)‐protein kinase that plays a central role in regulating cell growth and proliferation.33 Overactivation of AKT/mTOR after phosphorylation is associated with over‐proliferation of leukaemia cells,16, 34 as well as tumour cells such as liver cancers and pancreatic neuroendocrine tumours.35, 36 Our study found that p‐mTOR and p‐AKT decreased in CD8+ T cells after co‐culture with exogenous Gal‐9, indicating that TIM3/Gal‐9 pathway might suppress CD8+ T cells through down‐regulating AKT/mTOR (Figure 6C). Here, LGALS9 is linked to leukemia.