Evaluation of Sphingolipids as Predictive Biomarkers of Immune Checkpoint Inhibitor Response in Melanoma Patients

Inclusion Criteria: 1. Age ≥18 years at the time of study entry. 2. Patient with histologically-proven metastatic and/or unresectable melanoma (stage IIIc-IV, M1a-c as per AJCC 8th edition), including mucosal melanoma, without intracranial active disease. 3. Patient for which a treatment with immune checkpoint inhibitor (nivolumab alone, pembrolizumab alone, nivolumab plus ipilimumab) has been decided. 4. Subjects are included regardless of BRAFV600 mutation status. BRAFV600 mutation status must be documented. 5. Patient must be naïve to immune checkpoint inhibitor treatment for locally advanced and/or metastatic disease (i.e., no prior treatment with ICI and current treatment with ICI not yet started). 6. ECOG Performance status 0-2. 7. Life expectancy of at least 3 months. 8. Patient able to participate and willing to give informed consent prior performance of any study-related procedures and to comply with the study protocol. 9. Patient affiliated to a Social Health Insurance in France. Exclusion Criteria: 1. Patient pregnant, or breast-feeding. 2. Uveal melanoma. 3. Any condition contraindicated with sampling procedures required by the protocol. 4. Any psychological, familial, geographic or social situation, according to the judgment of investigator, potentially preventing the provision of informed consent or compliance to study procedure. 5. Any current severe or uncontrolled disease, including, but not limited to ongoing or active infection. 6. Patient who has forfeited his/her freedom by administrative or legal award or who is under guardianship.