At WWDC 2017, Apple announced the new Files app that would be shipping with the iOS 11, this fall. Although the app looks pretty basic as a simple file explorer kind of thing, but Apple has put in a lot more effort for it to be your once place for managing all your personal and work related files locally or somewhere on the cloud with minimal effort and greater reliability. That’s why the new Files app will support third-party cloud integrations like OneDrive, DropBox, Box etc. Speaking of which, Microsoft has officially announced that its cloud-based file management tool, OneDrive would be able to work with the newly announced Files app.
This will make it easier for you to access your content from any Apple device, and provide a better OneDrive experience on every platform. As you are already aware of the fact, OneDrive already supports many iOS capabilities, including OneDrive for iMessage, the Share extension, and Apple Pencil and split-screen support on iPad.
Microsoft will be sharing more details as iOS 11 nears release, this fall.
More information on Files app can be found here