Mic monitoring wasn't always a thing. In fact, it has only become prevalent in video games within the past decade.
In short, mic monitoring gives the player the ability to hear themselves while playing.
This has a few key benefits.
The first benefit of mic monitoring is the reason why it was created. When people can't hear themselves, they have a tendency to talk louder than they would if they could listen to themselves.
This led to an uncomfortable experience for people on the receiving end of the microphone.
Mic monitoring makes it so that the person talking into the microphone is able to hear themselves, so they are better able to adjust their talking volume so it's realistic and comfortable.
How do you turn on mic monitoring?
This is dependent on the device you're on. Most devices that allow you to add a microphone have microphone settings where you can adjust the mic volume, its input, EQ, and sometimes other settings. Most of the time, you can find the option to turn on mic monitoring here.