IDO1 and glioblastoma: Specifically, the positive association between NUCB2 expression and several immunoinhibitory molecules, such as IL10RB, PDCD1LG2, IL10, IDO1 and CD96, suggests that NUCB2 may facilitate the establishment of an immunosuppressive microenvironment, potentially accounting for the paradoxical observation that increased immune infiltration correlates with poorer clinical outcomes in GBM patients.