Knowledge of these alterations, both in the molecular pathways that modulate T cell activity in CLL (the T lymphocyte cytotoxic antigen-4 (CTLA-4) axis and programmed cell death 1 (PD-1)) and at the T cell immunoreceptor level, could be of interest as therapeutic targets in CLL. This evidence concerns the gene PDCD1 and B-cell chronic lymphocytic leukemia.