To determine how the activation of CLL cells within the tumor microenvironment affects the cytotoxic effect of venetoclax, we treated cells derived from nine patients with CLL with 1 nM venetoclax alone and in combination with 100 ng/mL IFNγ, 10 nM PMA/ 1 μM ionomycin, and 100 ng/mL sCD40L for 24 h. Here, CD40LG is linked to B-cell chronic lymphocytic leukemia.