When we studied the phenotype of venetoclax-resistant CLL cells induced by activated T cells, we found that they showed an aggressive phenotype characterized by higher CD86, PD-1, Ki-67 and MCL-1 and/or BCL-XL expression with sustained resistance to a second treatment with the drug (11, 12). The gene discussed is BCL2L1; the disease is B-cell chronic lymphocytic leukemia.