Planner (the Office 365 solution to help you manage project plan and tasks) and Who (a Teams app to help you search people within your organization) have been integrated to Microsoft Teams.
When I say integrated this does not mean you have to search and add these apps, there are inside the Teams client; just check the 3 dots (…) just below the Files option
Then when you launch them, these applications will be displayed directly within the Teams client
NOTE you may be requested to authenticate again
