A couple of weeks ago, Microsoft announced a couple of new features for Planner including Outlook calendar integration. This feature is now available today, and Planner users can now import all their Planner tasks in their Outlook Calendar via an iCalendar feed.
Microsoft says that Outlook calendar sync in Microsoft Planner is automatically turned on for all organizations that have Planner as part of their Office 365 subscription. To check if it's enabled, you can go to "My Tasks" in Planner and click the ellipses (...). You should then see a dialog box with the iCalendar feed, as well as an "Add to Outlook” button you'll need to click.
Once you're done, your Planner tasks should appear in Outlook for Web as well as the Outlook desktop app. On the web, you can toggle this calendar on and off on the left bar under "Other Calendars." Because this Outlook integration all works through an iCalendar feed, be aware that there may be a slight delay before new Planner tasks appear in your Outlook Calendar.
This is a pretty useful addition overall, and Microsoft explained that you can pick specific plans to import in Outlook in addition to the tasks assigned to you. We invite you to check this support page in case you need more information.