Most of the characters in Mercenaries Mode in Resident Evil 6 have alternate costumes that you can unlock.
Here are the costumes you can unlock, and how to unlock them.
Ada’s White Dress – Get an A rank or better with Ada in Mercenaries Mode
Chris’ Samurai Outfit – Get an A rank or better with Chris in Mercenaries Mode
Helena’s R.P.D. Outfit – Get an A rank or better with Helena in Mercenaries Mode
Jake’s Puffy Jacket – Get an A rank or better with Jake in Mercenaries Mode
Leon’s Pirate Outfit – Get an A rank or better with Leon in Mercenaries Mode
Piers’ Racer Outfit – Get an A rank or better with Piers in Mercenaries Mode
Sherry’s School Girl Outfit – Get an A rank or better with Sherry in Mercenaries Mode
Check out my other article for a complete list of cheats, unlockables, tips, and tricks for Resident Evil 6.