Grand Inquisitor

Both have a bakery setting where the main, BL relationship takes place.
Similar aesthetics in both with all the tasty cakes and bright, happy colours.
Both main characters have a mysterious, traumatic past, though in CY, it isn't really mentioned after the 1st episode, while in AB, it is a plot line.

Overall, both have Cute boys and yummy cakes !

Both are similar in that there are two male leads who have known each other since they were young and now work together in solving crimes through detective work. Both shows have a heavy bromance.

Both shows delve into human psychology and have a main character that is teetering between good and evil while the other main character is determined to keep them in the light,

S.C.I has a higher production value and is more action-oriented while RHGHHnS is more akin to Sherlock and solving mysteries. Both are excellent!

Both are Japanese detective mysteries where there is an insanely smart and quirky main character who, along with their charming partner, solve crimes and mysteries.

If you like Sherlock Holmes, mysteries and bromance, then you will like both of these shows.

Both are stories that are focussed on the male leads trying to protect each other from evil whilst keeping a huge secret. They both surround mystical elements and have enjoyable side-characters that have their own story arcs and developments. They also share the similarity of having over 40 episodes, so both are long series,

L.O.R.D and Guardian both have an enjoyable bromance between the main leads.