Use standard Mac keyboard shortcuts
There are many apps like Teams where hitting the return key after entering text "posts" the text in whatever way makes sense for the app. The Mac standard is to type option-return to insert a newline into the message (since just return does something else). Teams uses shift-return instead. I wish that Teams would use the Mac standard.
Ben Coppock commented
This is a huge deal. Muscle memory for Mac users means it's common to trigger the wrong action when attempting to use standard Mac shortcuts.
Option + Return is the correct way to get a newline on a Mac — please give a newline and don't submit the message when we use that shortcut!