As for returning for Deadpool 3 or a possible X-Force movie as Cable, that is unclear for Josh Brolin at the moment.
Josh Brolin says that working on Deadpool 2 felt like a “business transaction” when compared to the freedom he had while making Infinity War and Endgame.
The Russo Brothers and Josh Brolin enjoyed their experience of making Infinity War and Endgame together, even though it was a massive undertaking.
You can check out the entire interview with Josh Brolin over at the Team Deakins Podcast.