ENTPD1 and neoplasm: CD39 expression in MDSCs is positively correlated with NSCLC tumor stage, but its function remains unknown.511 Due to its important role in the TME, CD39 has become an emerging target for researchers to develop tumor immunotherapy.512,513 In vivo and in vitro data suggest that targeting CD39 sensitizes tumors to PD-1/PD-L1 ICB treatment.