It depends on a few factors; is the application pinning certificates? If not, can you load a CA onto the device. If not, can you issue a trusted cert to your MI

It depends on a few factors; is the application pinning certificates? If not, can you load a CA onto the device. If not, can you issue a trusted cert to your MITM proxy? Then you get into modifying the application itself by patching out checks, replacing embedded certs... It's also very handy to have a rooted device or emulator to hand too for times when you might want to poke around in the private storage of an app.