CTLA4 and melanoma: While there was no suitable therapy for metastasized melanoma available until about a decade ago, prognoses of melanoma patients have substantially improved in recent years, due to the identification of activating BRAF mutations in about 50% of melanoma patients [3,4], the use of selective inhibitors for BRAF and MEK, as well as the development of immune checkpoint inhibitors such as anti-CTLA4 and anti-PD1.