The spectrum of therapeutic options for CML patients has been enriched by second-generation TKIs, such as nilotinib, dasatinib and bosutinib, all of them approved for first-line treatment and being more potent and/or selective than imatinib in BCR::ABL1 inhibition. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.