E. Representative hematoxylin and eosin (H&E) staining and immunostaining for CD8, p-STAT3, p-AKT, and ARG-1 of tumors treated with vehicle, TP-16, anti-PD-1 antibody, or TP-16 and anti-PD-1 combined. Scale bars, 500 μm (left images), 50 μm (right images). 