IDO1 and neoplasm: Two distinct TME themes emerge near the tumour‐immune boundary. In the first theme, immune cells co‐express high levels of indoleamine‐azole 2,3‐dioxygenase (IDO), programmed death ligand 1 (PDCD1), integrin αM (CD11b), and integrin αX (CD11c). The second theme is located closer to or directly at the tumour‐immune boundary itself. Immune cells in this theme also exhibit elevated expression of CD45 and FOXP3, indicative of immunosuppressive regulatory T cells.