BCL2 and B-cell chronic lymphocytic leukemia: VEN is the world’s first oral, small molecule, selective inhibitor of B-cell lymphoma factor-2 (Bcl-2) for clinical use, which has been approved by FDA in 2016 for the treatment of adult chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), and then approved in many countries and regions including the European Union, Canada and China [1,2].