With Shared Calendars, Outlook users will be able to see who they're sharing their calendar with. In order to do that, they should just tap on the settings wheel next to their calendar's name.
Aside from the option to see who you're sharing the calendar with, you will also be able to see the default permissions that other in the same organization have.
In addition, Outlook users on iOS will be able to share their calendar with other people, as well as edit permissions or even remove them without having to access the app from the computer.
Based on Microsoft's new Acompli acquisition, the Outlook client for the iOS platform received quite a few updates in the last couple of months.
The new version of Outlook for iOS has already been released in the App Store, so make sure you update your app if you already have it installed so that you can take advantage of the new Shared Calendars features.