Microsoft started branching out in mobile a few years ago when it became apparent Windows Phone wasn't going to work out. One of the apps that came out of the so-called "Microsoft Garage" program was Arrow Launcher. It was a reasonably popular app in the Play Store, and now Microsoft is giving it renewed focus and a new name. It's the Microsoft Launcher now.
The Microsoft Launcher includes features from Arrow Launcher like Bing integration and the control center panel at the bottom of the screen. The interface is much more refined, though, and there's more Microsoft in the Microsoft Launcher. There's a folder of Microsoft apps on the home screen even if you don't have the apps installed. In place of the Google Feed you'd see on a lot of Android launchers, this one has a feed of content curated by Microsoft and pulled from your account. If you don't sign in with an MS account, this section isn't as useful.
Customization is a big part of the Microsoft Launcher, which includes various themes, icon packs, and feed options. It's also designed to plug into Windows 10, provided you are running the latest Fall Creator's Update. That enables the "Continue on PC" feature that syncs your photos, documents, and other content to your computer automatically.
The updated Microsoft Launcher is in beta right now, so you'll have to join the testing program if you want to check it out.
According to Microsoft's Joe Belfiore, Microsoft Launcher is now ready to graduate from beta to stable, with the gradual rollout beginning yesterday. The latest version is available for sideloading from APKMirror.
Also.. MICROSOFT LAUNCHER starts it's rollout from beta to "launched" today. Everyone with Arrow Launcher will get migrated gradually.
— Joe Belfiore (@joebelfiore) October 12, 2017