From the biological standpoint, little is known about PD1/PD-L1 axis in RS, however studies show how, differently from CLL, tumor cells in RS overexpress PD1 thus determining an impairment of T lymphocytes anti-tumor functions; for such reasons the PD1/PD-L1 axis could be a valid candidate for immunotherapy of RS (105). Here, CD274 is linked to B-cell chronic lymphocytic leukemia.