Teams unmutes my mic if I join a meeting with only one or two people in it. Even if I muted it from the button on my headset. It is the stupidest thing ever.
https://www.youtube.com/watch?v=utqEHuoq1iA
Edit: it seems like you can't set custom keybindings for PTT. Which is... idiotic. I usually use ` instead of whatever (habit from gaming on voice chats).
PTT requires you hold the keybind down, rather than having an always-on or always-off mic. (great if you just need to say something quick)