According to the job listing, the new IP by Guerrilla Games will feature online multiplayer, singleplayer and co-op experiences, however no other information from the studio has been given.
Luckily though, a bit of information has leaked from an insider, who also leaked content on the PS4 1.70 update, so although the information from the tipster may be false, it's pretty likely the information shared could be pretty on track with Guerrilla Game's plans for the future.
The insider revealed that Guerrilla Games plan to reveal their new game at E3 this year, and despite Killzone Shadowfall selling over 2 million copies, it's definitely clear that the upcoming game will be a completely new IP.
Like all of Guerrilla Game's titles, the new IP will be exclusive to Sony, and will be developed for PlayStation 4, making it the second title Guerrilla Games will have on the console. Considering that Guerrilla Games have experience with the Killzone franchise, it could be possible that the new game offers some sort of shooter experience, but at this point in time there's no real way of knowing.
We'll have to wait for Guerrilla Games to unveil more information on their upcoming IP, but hopefully we will all be in for a treat this year at E3.