CCL21 promotes the infiltration of T cells and dendritic cells into tumors, thereby enhancing immune activity (Sharma et al., 2020), and the synergistic tumor-suppressive effects of the combination of CCL21 and ICI in lung cancer and pancreatic cancer mouse models (Salehi-Rad et al., 2017; Chen et al., 2021). This evidence concerns the gene CCL21 and lung carcinoma.