It looks like IO Interactive found a new publisher for HITMAN and that publisher is none other than Warner Bros. Interactive Entertainment. This deal between the two companies will have WBIE publishing the physical retail release of HITMAN: Definitive Edition for the PlayStation 4 and Xbox One starting on May 15, 2018. It seems as though this release will include some additional bonus content by way of special outfits.
The HITMAN: Definitive Edition will include the following content:

From what I can see in this announcement, there is no word on whether or not those who already own HITMAN will get any of those bonus outfits. I'm guessing they probably will since IO Interactive has been pretty good about releasing new content for the game, but there's no official word on this. There's also no word about a PC release for any of this.

Just in case you needed a reminder about what's in the GOTY edition, I have you covered.