Although BTK inhibitors (e.g., acalabrutinib [ABT], ibrutinib [IBT], zanubrutinib [ZBT]) improve outcomes in multiple subtypes of B cell lymphoma and leukemia, BTK, and other Tec protein tyrosine kinases signal diverse cellular processes in immune cell lineages (e.g., macrophages, neutrophils, γδ T cells) (21–24). The gene discussed is BTK; the disease is leukemia.