In PML-RARA mice, the remission following ATRA treatment was accompanied with normalized levels of PGD2, ILC2s, M-MDSC, and a recovery of activated CD8+ T-cells. T-cell depleted APL B6 mice showed a shorter survival and an increase in ILC2 and M-MDSC. The increase in PGD2 and a major accumulation of ILC2 and M-MDSC upon leukemia engraftment were observed in HIS APL mice that were reverted by ATRA therapy. This evidence concerns the gene CD8A and leukemia.