CCL21 and neoplasm: When administered intra-tumorally in melanoma mice, ZCCG activated the cGAS-STING and TLR9 pathways, inducing the secretion of chemokines CXCL13, CCL19, and CCL21, promoting DC maturation, enhancing lymphocyte infiltration, producing pro-inflammatory cytokines, and inducing TLS formation in the tumor, ultimately inhibiting tumor growth.542 Additionally, a potent anti-tumor nanoscale peptide hydrogel (MRM-coated spores) was reported to increase CXCL9 expression, promote CD8+ T cell responses, and induce M1 macrophage polarization.