In myeloid derived suppressor cells (MDSCs), serine/threonine kinase PIM1-mediated phosphorylation of STAT3 at the S727 site enhances STAT3 transcriptional activity and leads to increased PPARγ expression, which in turn enhances FAO expression and promotes melanoma cell resistance to PD-L1 treatment [164]. Here, STAT3 is linked to melanoma.