Immune profiling of these preclinical melanoma models by flow cytometry, together with T cell depletion experiments and adoptive cell transfers showed that Activin-A inhibits anti-tumor immunity by attenuating CD8+ T cell infiltration, correlating with diminished secretion of the chemokines CXCL9 and CXCL10 by myeloid cells. Here, CXCL9 is linked to melanoma.