CD274 and glioblastoma: Our results concerning the up-regulatory role of Ang II/AGTR1 signaling on PD-L1 expression sustaining immune tolerance in glioblastoma cells, even though extremely promising, need to be corroborated by further studies related to the immunosuppressive effects of angiotensin on the tumor microenvironment by performing a more proper experimental model that represents orthotopic implantation of glioblastoma cells in syngeneic mice.