PDCD1 and cancer: Delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, delphinidin (DC) and gallic acid (GA) decreased the immune checkpoint, programmed cell death protein-1 (PD-1) and programmed death-ligand-1 (PD-L1), in HCT-116 and HT-29 cells, and thus showed the potential to activate the immune response in the tumor microenvironment and induce cancer cell death [98].