Mole people are not real, they are just a made-up scary story that people tell each other. The story goes that there are people who live underground all the time and they never come up to the surface. These people are called mole people because they are like moles who dig tunnels underground.
But it's just a story, there is no proof that there are really mole people living underground. There might be some people who live in tunnels or caves for a little while, but they always come back up to the surface eventually. So don't be scared of the mole people, they are just a silly story.