Ibrutinib, an oral Bruton’s tyrosine kinase (BTK) inhibitor, was approved by the FDA in 2013 and by the NMPA in 2017 for the treatment of patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) who have received at least one prior therapy [1,2]. Here, BTK is linked to B-cell chronic lymphocytic leukemia.