Until now the Executive Assistant could see your mailbox and calendar but not Teams. It now lists the teams you belong to, the channels in them, and reads channel messages and your chats, newest first, on the same connection it already holds for mail and calendar.

Your existing connection predates the Teams permission, so the assistant hands you a reconnect link the first time you ask; it takes a few seconds. Reading channel messages needs your tenant admin's consent once. A team you joined as a guest of another organisation is outside what your own organisation's connection can see; the assistant says so rather than report it as missing. Reading only: the assistant does not post in Teams.