Coexpression of PD-L1 and IDO1 was correlated (Pearson r = 0.67, P < 2.2 ×10−16, t test) across 11 granulocyte, macrophage, monocyte and DC populations (Fig. 3a,b and Extended Data Fig. 4a,b) and was highest in CD11b+CD11c+ macrophages (Fig. 3b and Extended Data Fig. 4b), a phenotype identical to that of a recently described immunosuppressive tumor-associated macrophage36. This evidence concerns the gene IDO1 and neoplasm.