CD4 and B-cell chronic lymphocytic leukemia: Treatment with IMiDs can lead to increased T cell activation and proliferation, by upregulating the release of pro-inflammatory cytokines (e.g., IFN-γ, TNF-α and IL-2) and downregulation of exhaustion-associated marker PD-1, increasing the number of functional CD8+ and CD4+ T cells and promoting an increased ratio of Th1 versus Th2 subsets in CLL [25,61,62].