Two independent melanoma patient cohorts (88 and 34 patients) treated with nivolumab or pembrolizumab were analyzed regarding baseline GDF-15 serum levels…. In melanoma, patients with higher GDF-15 levels have significantly shorter survival and are less likely to respond to anti-PD1 therapy...Consequently, GDF-15 may serve as a predictive biomarker for anti-PD1 response and potentially represent a novel target in the immunotherapy of cancer to improve tumor immune cell infiltration and anti-PD1 response.