Additional Study Information: The purpose of this study is to find if adding the study drug, nivolumab (also known as OPVIDO), will limit lung cancer from growing back in patients with early stage non-small cell lung cancer. Nivolumab is a drug that may turn on the body's immune system to attack any cancer cells that may remain after surgery. The addition of nivolumab may help prevent your cancer from returning, but it could also cause side effects. This research study will allow researchers to find out whether this different treatment is better, the same, or worse than the usual treatment for lung cancer. The study drug, nivolumab, is already FDA-approved for use in non-small cell lung cancer that has previously been treated with chemotherapy. The use of nivolumab in this study is investigational (not approved by the FDA) in your type of cancer. It is anticipated that there will be about 714 people taking part in this research study.