IDO2 and sarcoma: To better estimate the response to immunotherapy, we investigated the expression of inhibitory immune checkpoints (PD-1, PD-L1, CTLA-4, TIM-3, BLTA, ADORA2A, LAG-3, TIGIT, IDO-1, IDO-2, NOX2, VSIR, B7-H3, and VTCN1) (Dancsok et al., 2019) between high- and low-risk sarcoma patients.