When someone leaves a comment on a task within Planner, other's assigned to the task get a teams message and/or email to advise them a comment has been left. At present the only way to identify a comment is to fully open the task within the planner screen.
If I am saying the same thing as Jack, forgive me. I get an email telling me that an update has been made in Planner via Teams. When I click on the link in the email, it takes me to the browser version of Planner, not to the Teams app. Why all this work outside Teams? The kool-aid I have been given is that I can do all my work from within Teams!?