IDO1 and neoplasm: Invasive bladder cancer involving the MIUBC activates tumor oncogenic pathways associated with T cell exclusion, which is typically indicative of a poor prognosis.748 In T cell-inflamed muscle-invasive urothelial bladder cancer (MIUBC), commonly upregulated genes include those encoding PD-L1, IDO, and FOXP3 (the main regulator of Treg cells).