IDO1 and neoplasm: performed the first study capturing features and the spatial orientation of immune cells within the TME via MIBI from 41 TNBC patients (56); they divided tumors into cold, mixed, and compartmentalized subtypes by assessing the spatial proximity of cell types, and highly ordered structures with PD-L1 and IDO along the tumor-immune border served as a dominant feature of tumor compartmentalization and were associated with favorable survival.