As to what that IP is, both Square Enix and Forever Entertainment are, unfortunately, keeping mum and choosing to withhold that information from the masses. Until a time they deem to be appropriate, naturally.
It’s not a secret that Square Enix has been on something of a remake kick of late, the most obvious example being last year’s release of Final Fantasy VII Remake, although the entirety of the remake was handled internally. It is also undeniable that the company has a sizable library of video game IPs that includes the Tomb Raider and Deus Ex franchise.
In any case, it’s clear that we’re all just going to have to adopt a wait-and-see stance with the two studios. Who knows, maybe we’ll hear something during the digital platform at E3 this year.