can unity application integrates with Microsoft vs application? (integrating two applications)

I know unity can integrates with VS for scripting, I was wondering if the application developed in unity can integrate with the application developed in MSVS? More specifically, I developed the user interface of my application in MSVS, and I want to develop the game-based simulation module in Unity and to integrate with the UI, does anyone know how to integrate two applications? (both in c#)