Despite practice changes in treatments, such as the introduction of tyrosine-kinase inhibitors for BCR::ABL1+ in chronic myeloid leukemia (CML), or Bruton tyrosine kinase (BTK) and BCL2 inhibitors for chronic lymphocytic leukemia (CLL), these longitudinal sample collections remain highly relevant for translational immunologic research.76 Here, BTK is linked to B-cell chronic lymphocytic leukemia.