BTK and B-cell chronic lymphocytic leukemia: According to the National Comprehensive Cancer Network (NCCN) guidelines for CLL (2020 version), in frail patients with significant comorbidity, patients aged ≥65 years, and in younger patients with significant comorbidities, with or without del(17p)/p53 mutation, the preferred first‐line therapies include ibrutinib (a Bruton's tyrosine kinase [BTK] inhibitor), acalabrutinib (a second‐generation BTK inhibitor) alone or in combination with obinutuzumab (an anti‐CD20 monoclonal antibody), and venetoclax (a BCL2 inhibitor) in combination with obinutuzumab.3