I tried
GameObject.CreatePrimitive(PrimitiveType.Cube);
But nothing happens.
I tried
GameObject.CreatePrimitive(PrimitiveType.Cube);
But nothing happens.
That just returns a gameobject, you then need to Instantiate it.
Instantiate(GameObject.CreatePrimitive(PrimitiveType.Cube));
Create primitive will create an in scene object. No need to Instantiate.
You can also simply call new GameObject, which is often more relevant then creating a cube.