thanks the patients, nurses, and physicians involved in opdivo clinical trials. finally tonight here, america strong. the little girl and her fighting spirit already seen by millions. reporter: this is how the video starts. her shoulders moving. little leah. lip syncing to start. she s just 4 years old. born with a rare blood disease a thumbs up. after overcoming two bone marrow transplants. her mother by her side there. and on the video, mom encouraging her little girl. let me hear it.