ENTPD1 and hepatocellular carcinoma: HCC-derived exosomal circTMEM181 sponged miR-488-3p and elevated the expression of the CD39 in macrophages and the expression of the CD73 in HCC cells, which collaboratively stimulated the eATP-adenosine pathway and generated more adenosine, damaging CD8+ T cell function to indulge immunosuppression and acquire anti-PD1 resistance in HCC (88).