However, compared to solid tumors, where anti-CTLA-4 blocking antibody ipilimumab is widely adopted with significant benefits for patients [46], this approach has only recently entered the clinical practice for hematological disorders and few trials are currently ongoing in CLL (NCT01822509, NCT00089076; www.clinicaltrials.gov) [47]. Here, CTLA4 is linked to B-cell chronic lymphocytic leukemia.