BCR and chronic myelogenous leukemia, BCR-ABL1 positive: Several lines of evidence demonstrate that CML responds well to immunotherapy, including treatments such as interferon‐α, allogeneic hematopoietic stem cell transplantation, and donor lymphocyte infusion [8]; however, even if PCR no longer detects BCR::ABL1 mRNA, a small number of CML cells are thought to remain.