Respawn sure seems to be busy right now - not only is it beavering away on Apex Legends (and reportedly a sequel to Star Wars Jedi: Fallen Order), but we've also heard news about a new IP - and it seems this one is going to be a single-player game.
A number of new job listings have been posted on Respawn's website, with creative director Mohammad Alavi describing the project as a "brand new Respawn single-player adventure". Details on the game remain light, but the postings do note that the project is "in its early stages", while the single-player title is apparently "a designer's dream playground with a freedom to innovate made possible by the unique universe it inhabits."
According to a tweet in April by Respawn developer Steven Kah Hien Wong, the team is building a new IP "from scratch". So before you start asking about Titanfall 3 again, it seems like this is something brand new.