FD therapy has been explored in previously untreated patients with CLL by using two different strategies, combing venetoclax with either an anti-CD20 monoclonal antibody (Ab, i.e., rituximab or obinutuzumab) or a BTK inhibitor (BTKi, such as ibrutinib, acalabrutinib or zanubrutinib). The gene discussed is BTK; the disease is B-cell chronic lymphocytic leukemia.