Melanoma is the most aggressive among all skin cancers and is responsible for high mortality rate. Combined immunotherapies have demonstrated a greater efficacy to boost the immune system of melanoma patients. However, the clinical decision on which combination to be used and which patients will benefit the most from it, remains a challenge. Understanding the immune context of patients’ tumor and the identification of reliable biomarker redouts will assist clinicians in their decision. We developed a multiplex immunohistochemistry assay to profile the tumor microenvironment of metastatic melanoma patients who responded or not to combined immunotherapy. We used LabSat®, an automated stainer based on Lunaphore’s microfluidic technology, to analyze the expression of PD-L1, CD8 and LAG-3. Our results provide first-time evidence of a different expression pattern of these markers between responder and non-responder melanoma patients.