Duality

Duality is a third-person action game (like Oni and Strident), which (like Strident) was developed by Phantagram a.k.a. Trilobite Graphics and (like Strident) was eventually canceled despite being rather promising.

Trailers

There are two trailers. Neither of them is overly exciting.

First trailer

The trailer follows a Hacker (she) and a Mercenary (he) as they break into a heavily guarded facility, steal some important stuff, and then escape.
The Mercenary uses regular stealth, acrobatics and weaponry, whereas the Hacker spends most of the time in cyberspace fighting weird monsters.

Segmented/incomplete version on IGN's YouTube (6 segments): 1 2 3 4 5 6

Full version on geyser's YouTube (mirrored from HERE): Duality trailer (canceled game)

The segments published by IGN are dated April 8, 2002, and labeled "Gameplay", although the trailer is clearly staged/rendered (not unlike this one)

Second trailer

This trailer is higher-resolution and shows some actual gameplay (mostly stealth), as both the Mercenary and the Hacker make their way through enemy territory.

Full version on some guy's channel dedicated to canceled games: Duality [XBOX Trailer Action/Stealth - CANCELLED!]

The final sequence of that second trailer is a hint at the third playable character - the "Virtual Being". Apparently it plays chess.