In our laboratory, we demonstrated that tumor-derived sonic hedgehog (Shh) ligand promotes M2-polarization of TAMs to suppress CD8+ T cell infiltration through downregulation of CXCL9 and CXCL10 and limit effector T cell functions by upregulating programmed death ligand-1 (PD-L1) expression on TAMs [24,27]. Here, SHH is linked to neoplasm.