The purpose of this study is to compare the usual approach (i.e. no more treatment or additional post-operative chemotherapy), to any effects, good and/or bad, of the experimental drug MK-3475 (also called pembrolizumab) after surgery.
This study will allow the researchers to know whether treatment with MK-3475 (pembrolizumab) is better, the same, or worse than the usual approach. There will be about 1,000 people taking part in this study across all research sites.