CD4 and neoplasm: Despite all the data referred to above regarding the potential crucial role of T-cells and certain T-cell subsets in controlling tumor growth, whether the T-cell populations here found to be expanded in CLL are tumor- or CMV-specific T-cells, as well as their precise functional role and active vs. senescent/exhausted status, deserve further investigations in larger series of patients, to better understand the precise role of TCRαβ CD4+CD8lo T-cells (and other adaptive and innate cells) in the tumor microenvironment and the kinetics of the CLL clone in blood.