One of for "New Challengers" in the fourth Street Fighter II revision, Cammy is a teen-aged agent of Delta Force Red within Britain's MI6. The game had 2 different endings for her; the Japanese version depicts Cammy as a former agent of M. Bison's, but suffered amnesia during her last operation. In the American version of the game, however, she was revealed to be M. Bison's lover, who was also suffering amnesia.
Impressive cosplay! Though I don't recall seeing a white version of her costume. I only remember green and blue ones. In any case though, thanks to Illinoisiana for the photo!