https://wccftech.com/fortnite-is-now-available-on-google-play-epic-we-realized-doing-otherwise-puts-us-at-a-disadvantage/

Fortnite is now available for download on Google Play. Since its debut on Android, Epic Games had chosen not to distribute its hugely popular Battle Royale game through Google's own store.

The main reason for that decision has to do with Epic's open dislike of Google's mandatory 30% tax for apps and games sold through Google Play. However, failing to appear on the built-in Android store certainly translated into millions of lost potential customers for Fortnite, which is why Epic even petitioned Google (to no avail) to avoid enforcing that products distributed through Google Play use Google’s payment service for in-app purchase and, therefore, require a mandatory 30% fee.