This observation is consistent with previous reports that MAIT and γδ T cells act as a first line of defense, and they possess the potential to kill leukemia cells.[20] Treg cells were characterized by high expression of the Treg signature genes Foxp3, IKZF2, IL2RA, and CTLA4 as well as co‐stimulatory markers, including CD28 and ICOS. This evidence concerns the gene ICOS and leukemia.