Here, we used flow cytometry to assay the expression of the activation markers CD38, CD69, and human leukocyte antigen – DR isotype (HLA-DR), the IC molecules programmed death-1 (PD-1), B, and T lymphocyte attenuator (BTLA), and T cell immunoglobulin and ITIM domain (TIGIT), the co-stimulation marker CD28, and the immune senescence marker CD57 on different T cell subsets in PB and BM from CML patients. The gene discussed is CD69; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.