Aug 27 2017 02:23 PM
If you haven't noticed already: With the newest Project client release you can now link a task to Planner. From my early testing it is for the moment just that a link with an indicator at the task.
Some more details in the Planner group: https://techcommunity.microsoft.com/t5/Planner/Manage-a-Project-task-in-Planner/m-p/101121#M1078
Jul 24 2018 01:04 AM - edited Jul 24 2018 01:08 AM
It seems this feature will get a small update according to the O365 roadmap: