For IL-35 secretion in metastatic tumors, Tregs should be considered in addition to mTAMs since knockout of Il35 in mTAMs herein significantly reduced but did not completely abrogate metastatic colonization, and IL-35-mediated JAK–STAT6–GATA3 signals formed in metastatic tumors even with Ebi3−/− mTAMs. The gene discussed is EBI3; the disease is metastatic neoplasm.