Square Enix has filed a trademark for something called Outriders with the European Union Intellectual Property Office (EUIPO).
While there's no details as to what this could be, the filing does mention it pertains to 'game software' and 'entertainment services.'
So yeah, it's most probably a video game, then, and could very well by the new AAA title that the publisher is working on with People Can Fly.
We don't know anything about that particular project just yet, though People Can Fly announced recently that it's begun ramping up production of the game by opening two new studios.
On the other hand, it could be something else entirely. Hopefully we'll find out more at E3.
Square Enix is a pretty busy bee at the moment, with Shadow of the Tomb Raider, Kingdom Hearts 3, and Final Fantasy 7 Remake all on its current release slate. Well, okay, the latter is probably never going to see the light of day until 2020, but it's still happening.