I am gearing up to replace my old webcam with a DSLR/mirrorless, as an interesting technical exercise, to have a better looking Zoom/Skype/Teams, do some talking head video presentations at home and possibly livestreaming one day. But mostly as an interesting technical exercise, something to play with in lockdown. Gamers and vloggers have been doing this to livestream to Youtube, Facebook, Twitch and other platforms for ages. For cameras, this is a growing market
One of the prerequisites is a camera with a clean HDMI feed. Of all the big camera manufacturers, the only one not offering a DSLR or mirrorless camera with a clean HDMI output is Nikon. Canon and Sony are all over it, and the Panasonic GH5 is up there with the Sony A5100 onwards as a popular choice.