CCL19 and neoplasm: CXCL5, which releases from M2-TAMs, promotes an immunosuppressive tumor microenvironment53; CCL19 is a critical regulator in immune surveillance54 and proved to induce M1-TAMs chemotaxis but not M2-TAMs.55 Meanwhile, TAMs express PD-1 and PD-1/L1 blockade could effect on them to reduce tumor growth.56 Therefore, the effective immune response in this study may be related to the release of M2-TAMs immunosuppression after PD-1 antibody therapy, which required further investigation.