CD4 and chronic myelogenous leukemia, BCR-ABL1 positive: We have reported maximal restoration of immune recovery in CML patients on TKI occurs only following achievement of MR4.5 (BCR-ABL1 ≤0.0032%), as demonstrated by increased effector NK cell number and function and T cell immune responses, reduced numbers of PD-1+ CD4+/CD8+ T cells and monocytic MDSC (12).