Tribe already has a built-in support for PWA (progressive web app), which basically turns a website into a mini-app. Your user simply has to add Tribe community to their home screen to enable that support. When I visit Tribe or any other Tribe-based communities on my phone, I get a notification bar that asks me to add community to my home screen. You should have seen it if you ever visited your community on your mobile device.
Once added to home screen, when you open your community through the icon it will act as an app. It won't have the browser bar, etc. It will be full screen and behave as an app, but keep in mind it does need an internet connection to actually work.