Consistent with previous studies, our results also demonstrated that the level of PD-1+CD8+ T cells increased in the PB but not BM of DN-CML patients (18, 37), but taking a close look at the subsets, we found that CD8+ TEM and TEMRA subsets were mainly impaired, while the CD4+ TEM also affected. Here, CD4 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.