Bing to Index Content from iOS, Android, and Windows Apps

Bing is going to expand index of search results to add content from apps. Bing is actually building a massive index of content from mobile apps from various platforms — Windows, iOS and Android.

Bing to Index Content from iOS, Android, and Windows Apps : eAskme

Usually content on mobile apps is not searchable, indexable or crawlable outside of the app. Even Google is limited to Android apps only to index mobile app content.
Bing want to provide you the mobile app results in search results no matter which device you use. Bing calls this App Linking, and announced how SEOs can take advantage of this:
Bing clears that developers and SEOs need to apply to make app content searchable and indexable. If you are already know how to use Schema markup then you can easily understand these steps.
It is the best time to apply markup now. Bing is already crawling App Links. Till now Bing has not cleared when it is going to launch app content indexing but we can expect it soon.