It could easily take place after Resident Evil 5. Jill's new blonde look means next to nothing.
This is seriously like the most confusing game trailer ever. The guy in the chair looks like Chris but isn't Chris. Then, Jill points her gun at him then at the real Chris though since the guy in the chair isn't Chris but looks like him, real Chris might be another fake Chris and Jill might not even be the real Jill. Is Resident Evil headed down the clone plot device route? I guess that the only logical way to bring back the series' main villain.
At face value, it looks like the player takes control of Jill even though Chris narrates. There may be some Hunk levels too. This is shaping up to be like my dream Resident Evil game. Just give me Angela Miller and I might break and buy a 3DS when this comes out.