In hematological malignancies, BTLA/HVEM axis dysregulation decreased perforin and granzyme B production by BTLA+ T cells and was associated with poor outcome in DLBCL and FL, whereas only two studies reported about BTLA and HVEM expression on leukemic cells from CLL [42,51,55]. Here, GZMB is linked to B-cell chronic lymphocytic leukemia.