You might recognise this one, earlier this year it was announced, but then put on hold in March while Microsoft made some changes.

Short version:
This new Planner feature allows you to quickly add attachments to your tasks from an intelligently curated list of relevant files. The recommendations are based on you and the task. Due late May to early July.

Details:
This new Planner feature allows you to quickly add attachments to your tasks from an intelligently curated list of relevant files. The recommendations are based on you and the task.

You will be able to choose recommended files to add as attachments to your tasks in Planner:

Availability:
Microsoft will begin rolling this out in late May and expect to complete the rollout by early July.