Both have criminal psychologists/profilers as main leads
In both shows, the main leads solve different crimes, each of which offers more clues to a deeper conspiracy'
In both shows the main leads are trying to find the truth about a crime in the past that personally affected them

Both shows are based on novels from Ding Mo. they are actually sort of a loose series with When A Snail Loves being the first book in the collection
Both have a criminal psychologist/policeman pairing though When a snail loves deals with multiple types of cases including corporate/white collar crime and human trafficking

Both are fantasies though Moorim School is also a "school" story
The "vibe"s of the shows are pretty similar to each other
Pretty boys in both