What kind of story does the American drama X Files tell?

The main line of the X-files is about aliens. Everything goes back more than 60 years. In the 1940s, a UFO crashed in Roswell. The U.S. government randomly set up a special group to deal with alien incidents and crack alien technology. After gradually deepening the study of aliens, people found that there is something called black oil in aliens, which is fatal to human body. Therefore, the United Nations Security Council later passed a proposal that all countries must execute living foreigners.