There is a huge discussion between website owners about upcoming mobile-friendly-ranking-factors going to be update by Google on 21st April for mobile devices SERPs, but App Ranking is already live as a ranking factor in Google mobile search.
Google Announced on mobile ranking that Android Apps will rank better in mobile SERPs, when user is signed in and has the android app installed and it works like the app will do the app indexing.
This was overlooked for good reason:
(1) They grouped it with the mobile-friendly web site announcement.
(2) This only works for Android users that have your app installed and are signed in when searching.
(3) It only works with Android apps that have a web site counterpart and can use App Indexing.
Resource – https://www.seroundtable.com/google-app-indexing-mobile-ranking-live-20001.html