Anagliptin did not affect the expression of DPP4 in tumor tissues; both anti-PD-L1 and anagliptin alone could reduce the expression of macrophage-specific markers, F4/80, and the M2 macrophage-specific marker, CD206, in tumor tissues, while combined treatment significantly downregulated their expression compared to anti-PD-L1 treatment alone (Fig. 2c–e). Here, DPP4 is linked to neoplasm.