Assignments in Teams - What does "Not handed in" exactly mean?

Letizzzia Hello, I am not that familiar with Teams for education but it's related to the 'Assignment timeline'.

"Decide when assignments will post to students and whether you will accept turn-ins after the due date has passed."

I suppose the student did not make the due date, but could possibly have done something. See the links for more info

https://support.office.com/en-us/article/review-return-and-turn-in-assignments-using-the-feedback-loop-63e5efdd-be09-47f0-87ea-e8e4bcb45aa4

https://support.microsoft.com/en-us/office/turn-in-an-assignment-in-microsoft-teams-e25f383a-b747-4a0b-b6d5-a2845a52092b

Hope it helps!