In Eμ-TCL1 AT mice, BET-i reduced expression of IRs commonly targeted by checkpoint blockade (e.g., PD-1/PD-L1, LAG3, CTLA4) along with factors adding to redundant T cell suppression in CLL (e.g., CD244, Il10) and genes utilized by other immunosuppressive cellular contributors (e.g., Cd84, Entpd1, Adora2a) (54). Here, CD274 is linked to B-cell chronic lymphocytic leukemia.