I know you can currently deep link to the Messenger itself, but it would be really valuable to deep link to specific apps within the Messenger. As companies use more apps in their Messenger, the space gets crowded and harder to find certain things. Additionally, companies would likely prefer to link to an app within their Messenger (still within their app), rather than linking to a separate, 3rd party app. This way, they can keep their users within their app experience.
Is this something on your radar?