Microsoft is currently rolling out the Custom Background feature, which allows the background to be exchanged in a team meeting. This feature is based on the already known background blur feature.

While currently only predefined backgrounds can be selected, according to the Microsoft roadmap, it should be possible to upload and use your own backgrounds in May.
Those who cannot wait that long can already upload their own backgrounds now.

Just copy a picture in JPG or PNG format into the following directory:

Windows 10

~/Library/Application Support/Microsoft/Teams/Backgrounds/Uploads

I recommend to use a standard image size, for example 1920 x 1280 pixels. At the next meeting the new background should be available.

You can either select it before entering a meeting room:
Microsoft Teams Custom Background

Or while you’re already in a meeting:
Microsoft Teams Custom Background