One of the most iconic concepts introduced in Star Trek is the so-called "Mirror Universe," a parallel dimension in which doubles of heroic characters exist but evil. Created by Jerome Bixby for Star Trek: The Original Series, the concept returned in future series and was a significant part of the relaunch of the universe in 2017's Discovery. Of all the different Star Trek shows set in the Mirror Universe, which show did it the best? There are strong contenders, especially since the universe is different each time they revisit it.
Source：https://www.cbr.com/star-trek-discovery-mirror-universe-episodes/
