Despite being standard of care, there are still many medical requirements related to immune checkpoint blocker based therapies such as identify patients susceptible to respond with the less adverse events, evaluate the clinical benefit of adjuvant treatment /risk of relapse and design new strategies for non-responder patients.

Thus, this project aims at understanding the impact of anti-PD1 on the immune system through investigation of the phenotypic, functional, metabolic and transcriptomic profiles of circulating DC subsets and effectors in response to anti-PD1 therapy in melanoma patients.

The primary objective of the study is to identify the biomarkers of response to anti-PD1 according to the type of patient before the start of the treatment.

Inclusion Criteria:

• Patient with histologically confirmed melanoma (stage I, II, III or IV based on AJCC classification)
• Able to sign the informed collection consent for the retrospective part or to express their non-opposition to the research for the prospective part of the study

Exclusion Criteria:

• Subject under guardianship or subject deprived of freedom
• Persons benefiting from special protection (as defined in Articles L1121-5 and L1121-8 of the Public Health Code): minors, pregnant or breastfeeding women, adults protected by law (under guardianship, curatorship or deprived of liberty) and persons hospitalized without their consent (as defined in Articles L3212-1 and L3212-3 of the Public Health Code).
• ocular melanoma

Patients with unresectable (stage III) or metastatic (stage IV) melanoma, followed at CHU Grenoble - Alpes in Dermatology deparment for diagnosis, follow-up or recurrence of melanoma, and treated with immune checkpoint blocker in curative or adjuvant setting.