The new sharing experience is rolling to Microsoft Teams chat. When you drop/upload/select a file to be shared you can now define what the recipient can do with the file. This makes it possible to share files and prevent others from downloading them. And yes – this comes from the OneDrive so this capability is possible for any file you have in OneDrive for Business.
After having the file in the chat you can just click on the text to open sharing options.
Then you can choose to disable Editing, limit editing with a review mode and if you don’t allow editing you can Block download.
Review mode means the recipient can only leave comments and suggest changes – not doing actual changes to the text unless you confirm them.
And if you disable editing you can Block download.
I left disable editing and Blocking download on for this test.
When the recipient opens the file in Microsoft Teams they can see in the editor they are not able to edit the file.
And they are also blocked from downloading it
And no, File-menu doesn’t help them either.
What about other files in OneDrive for Business
Yes – you can do blocking the download for other files as well. This makes it possible to share meeting recording to others (externals) from your OneDrive for Business for viewing only – they won’t be able to download the recording!
Vesa Nopanen - My Metaverse Day 
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