ICOSLG and acute myeloid leukemia: Likewise, the expression of the inducible T-cell costimulator ligand (ICOSL) on acute myeloid leukemia (AML) cells, provided co-stimulatory signals for the expansion of ICOS + Tregs, which, through the secretion of IL-10 and TGF-β, led to immune evasion, further promoting the proliferation of AML cells [154].