IDO1 and neoplasm: Finally, our study showed a fibrosis-dependent T-cell exclusion mechanism in which TAMs and TILs were entrapped in peritumoral fibrotic areas expressing IDO1, PD-L1, and β-catenin (CTNNB1), suggesting tumour-driven immune exclusion, which can be associated as one of the causes of resistance to ICT in mUM with BAP1 losses.