This study is for participants that have been diagnosed with clinically detectable stage III-IV high-risk Melanoma. The investigational drug in this study is pembrolizumab. The purpose of this study is to compare outcomes of receiving the study drug either before and after or only after surgery for your type of cancer. Participants can expect to be followed for up to 10 years after they register to the study.

This study is for breast cancer patients who are making decisions about breast cancer surgery. This study is being done to learn about how patients and their surgeons make decisions about breast cancer surgery.