Ipilimumab, a monoclonal antibody, is intended for the therapy of pre-treated patients with advanced/metastatic melanoma. A phase III study showed an increase in median overall survival (OS) by more than 3 months for patients treated with ipilimumab in comparison to an experimental vaccine. As therapy of advanced/metastatic melanomas proves very difficult, this increase in OS can be called a success, especially since ipilimumab is the first therapy which demonstrated improvements in OS in pre-treated advanced melanoma. However, many open questions still remain including whether the comparison of ipilimumab to an experimental vaccine was a reasonable approach. In addition, adverse events were very frequent and sometimes life-threatening.