Activate scene from one program to another

So basically I would like to make two unity programs.
One has the main game while the other has a button which would activate a scene in the other game.
Does anyone have an answer? I’m using macOS and Net 2.1.

That will require some online implementation, try Unity’s Netcode for gameobject, it should allow you to control a scene from another Unity app as long as both apps are the same build.