Melanoma Stage III or IV

The goal of this observational study is to assess whether the IOpener® melanoma test can assist treating physicians in deciding which therapy is most suitable for patients with skin cancer (advanced cutaneous melanoma). For this purpose it is evaluated how well the IOpener-melanoma test can predict the result of cancer treatment in the treatment groups (standard of care anti-PD1 mono-therapy and standard of care anti-PD1 + anti-CTLA-4 therapy). Participants will be asked to provide blood sample for analysis using IOpener®-melanoma test. Patients will receive regular medical care, the test results will not be used to make any treatment decisions. The patients will visit the clinic for treatment administration and clinical evaluation as part of their regular medical care.