From the Endgame footage released thus far, Nebula and Tony Stark could be teaming up on a spaceship in order to join the remaining Avengers back on Earth, after they were the only two to be stranded on Titan at the end of the last movie.
Just getting back to Earth could lead the audience to root for the former villain, not to mention if she comes anywhere near giving Thanos the thrashing he deserves.
Nebula started off as a badass assassin not to be messed with in 2014’s Guardians of the Galaxy, but as her story has unfolded in the 2017 sequel and Infinity War, it’s clear the character could have a key role in what comes next.