BTK kinase inhibitors are powerful drugs designed to treat cancers arising from defective B cells, including chronic lymphocytic leukemia, B-cell lymphomas, and Waldenström macroglobulinemia. These inhibitors specifically target Bruton tyrosine kinase (BTK), a critical enzyme involved in B cell maturation and B-cell receptor signaling. Additionally, BTK plays a key role in activating myeloid cells responsible for producing inflammatory cytokines. These inhibitors represent a promising approach in cancer therapy.