Important observations were made by Alves et al. [113], who proved that CML patients treated with 2G TKI had a lower percentage of CD4+ Treg and granulocytic myeloid-derived suppressor cells (Gr-MDSC) compared to patients receiving imatinib (median CD4+ Treg 3.63 vs. 6.18%, p = 0.005 and Gr-MDSC 4.2 vs. 8.2%, p = 0.003), but higher levels of PD-1-co-expressing CD4+ cells (1.92 vs. 1.0%; p = 0.001). The gene discussed is CD4; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.