Both have a Swindler ML and are Japanese dramas. There’s a policeman in both that tries to help them. Both male leads had a tragic past and are actually quite kind.

They have in common : Bullying, vengeance, school fights, clever ML.
They’re also both based on a Webtoon.

Both are Japanese dramas who deal with swindlers and their victims. Both have one or more lead character(s) that has some kind of trauma from their past.
Sagideka is more focused on swindlers that use phone calls to trick people

It's same kind of movie, with the same vibe and kind of character. Also spies from North Korea in the south

Both have Kubozuka Yosuke
Both have this kinda Japanese 90s filming atmosphere
They sometimes give the same feeling, although IwGp is a drama and Go a movie