IDO1 and neoplasm: The 20-plex panel consisted of biomarkers directly targeting immune cells (CD3, CD4, CD8, CD11c, CD16, CD20, CD31, CD45, CD68, FoxP3, HLA-DR), non-immune tumor microenvironment (aSMA, CD31, PanCK, S100, Vimentin), features of the immunosuppressed microenvironment (IDO-1, PD-1, PD-L1) and the proliferation marker ki67 (Fig. 2C).