IDO1 and neoplasm: We can summarize the effects of resveratrol on macrophages and dendritic cells in tumor microenvironment to include the following: inhibition of M2 polarization of macrophage, inhibition of M2 macrophage activation, activates repolarization of macrophage from M2 to M1 phenotype, and inhibition of IDO expression and activity in dendritic cells.