He could've been a test subject/volunteer for one such plan. Once he reached his full potential, his body has started rejecting the treatments, via cellular decay, causing him intense pain. Amanda "The Wall" Waller ordered that he be terminated.
After barely escaping, desperate, he seeks out S.T.A.R Labs, as his body has continues rejecting the treatments the project subjected his body to. Superman himself is called in, shocked and angered at hearing of the project, he none the less agrees to help the soldier.
The suit he wears is very similar to the
Kryptonian recovery suit Superman himself wore once he was revived by 'The Eradicator', this one adapted for his very unique situation. It works, the suit stabilizes his cellular structure and allows him to use his new-found abilities, though, far less powerul then both Superman and 'The Flash', he's still a formidable opponent.
However, as his body is technically property of Project:Cadmus he's not seen the last of Amanda Waller.