Multiplayer Update
From Kerbal Space Program Wiki
The Multiplayer Update is the final formerly planned major update for KSP2 Early Access.
Features
The Multiplayer Update would add the ability to join a multi-player server and play with friends, either cooperatively or as a space race. 4 space agencies, each with their own space center, would exist on Kerbin. Space agencies could compete against each other, or cooperate by sharing resources.
Multiplayer was originally a planned feature for KSP that has now been moved to KSP2.