IDO1 and glioma: To better understand the immune-modulating functions of ISG20 in glioma, we estimated the correlation between ISG20 and a panel of immune checkpoint molecules, including PD1, PDL1, PDL2, CTLA4, TIM3, IDO1, and LAG3. ISG20 was significantly associated with these immune checkpoint genes (all r > 0.30, P < 0.001; Fig. 8A), suggesting an immunoregulatory role of ISG20 in the glioma immune microenvironment.