The Avengers lost a huge chunk of the team, so they need all the help they can get to beat Thanos once and for all.
It would certainly be fitting for Pepper to get in on the action in Avengers 4, potentially her last chance to do so.
Pepper has been in the MCU since the very beginning 10 years ago, and she’s mostly been relegated to the sidelines while Tony Stark flies missiles into portals or takes off to outer space to save a wizard.