Both have a female protagonist who is kind and believe in order and the police...
But when the push comes to shove.. she fights with her bare hands .. she enjoys her quiet life.. she enjoys her fights too...
Her image of a small, quiet female make her opponents understimate her.

She can be very naive at times.. and very perceptive about her fight surroundings and opponents.

She hates injustice..

A former spy in Okusa wa and an undercover agent in man to man..

Both series have a spy falling in love with an ordinary person.. involving him in his mess..and trying to figure out how to escape his destiny.. yell his partner the truth..and find a way to lead a quiet live with him/her.

The main protagonist likes to help people hurt by injustice..

(Protagonists in the series are from different genders, but..):

- both involve spy shenanigans and fights;
- cute adjumas who help them;
- protagonist have cute ordinary people they want to protect.., but involve in their mess

In Terius the main protagonist is a male and a still operating spy.. while in Okusama it's a retired female spy.. however.. both have in common:

- a spy moving into predominantly quiet family neighbourhood (or so it seems);
- gets a net of housewives as friends and
- becomes entangled in their problems..

In both.. the spies beloved one lives in the neighbourhood too..
Both are kind of romances..
Have spy shenanigans.

The dramas don't have many identical plot points, but both are :

BL romance dramas that involve a pair of identical twins in which one of them is straight and the other one is either gay or bi-sexial.
They involve their love wife.. the problems they have in their school and work-enviroment (as it involve students of high-school and colleague students.. and their close by age just started working adults)...
In both the twins have a family that doesn't support their love or life decisions.

Both dramas revolve around a group of young people who want to be voice actors. They start to revolve around a young girl with the same dream (the female protagonist). She is a fan girl of a certain person and is his greatest fan.

In If voice has memory the person she admires is a young person and they fall in love.. in Koeharu he is an elderly person and she auditions to be his voice actor.
In both she he is the person in which company she drives to be the most in.

Both dramas involve friendship between the voice actors.

In both BL dramas one of the couple's is between one regular person (whom is known for his great personality) and his very obssessive fan.

In Secret crush on you the obssessive guy feels a bit more disturbing.., but harmless towards the guy he lies.. In History 4.. the obssessive guy is shaming and not that harmless.. he is also a step-siblimg to the guy.

Both are BL romances.

Both have two people which are rivals at first. Both include a person whom knows he is a gay and another one whom is unsure..
Both dramas have the main people around the main couple (and the main couple included) have very messed up /kinky relationships (and include borderline abusive relationship).

In both the first sexual interaction between the couple feels like a rape from the point of the person whom is not yet realised he is gay. Yet the scene it's quite arrousing and visually stunning (steamy).

Both include atleast minor crimes.. and other dark stuff.

Both are BL romances and have a cute couple which include a shy older person (whom is having a cute little daughter) and a young vibrant person who likes to tidy up his life.

The thing I find similar in both dramas is actually the ending.
I would spoil the twist now:

[/spoiler]One of the two girls whom are friends in the drama is actually seeing a therapists and some of the events happening... Are not real.[spoiler]

Both are Korean romantic dramas that involve a romance between a person in debt and a debt collector.

You make me dance is a BL story.

One is a BL and the other isn't..

But
Basically both dramas have a successful businessman boss with a strong character who falls in love with a promising young chef who cooks traditional cuisine and makes him his employee (because he falls in hers/his food first).