I may say I did saw lots of such generic video game trailers but you didn't give any significant detail whatsoever. No year frame, no detail on how the girl is, environment, graphic style, art style, what it might be its target platform and all...
Not to mention it may not be from a cancelled game, it may be very early teaser, prototype and whatnot video that video games can change since their early announcements. For example years ago while I was exploring foreign channels on my satellite-connected TV I found a French channel showing a cool game about the young man who has typical Japanese "long but not too long long hair" throwing his Prince of Persia like long dagger around and where the dagger landed he was teleporting that location. So in the video we were completely seeing him from his back and he was running always forward. The video game had the impression that no matter what this character "moves forward" because at some point a tower was collapsing in front of him and he was zap zap teleporting inside of him and then the video ended when thus he reached a huge AF black monster. For a long time I thought it was a cancelled game or something because I didn't bump into any game like that, but then Final Fantasy XV released with the same mechanic lol so I gotta assume it was that game lol.
From the way you just gave little details it just reminds me Little Nightmares 1, perhaps it can be any game featuring a girl. If the girl is playable main character its rather easy to find by you because not many playable female character in existence to begin with.
store.steampowered.com
en.wikipedia.org
