Healer (2014)

The ML is a strong fighter who is sent to spy on the FL. The ML goes undercover to get close to the FL in a role where he is under the FL's authority. When the FL issues commands, the ML generally obeys and plays the role of a subordinate. The ML also becomes the FL's protector and saves the FL from harm on several occasions, even when it means risking his own life. And the ML does not let injury or illness get in the way of... intimacy.

One further parallel that is minor but amusing: the man who at first seems to be the ML's main romantic rival is later shown to have more romantic interest in a family member of the FL.

Both about internal politics, money and corruption. Both about underdogs who are trying to find out the truth of their parents' murder, while fighting for justice and the truth. Both involve protagonists who are close to/family members with the antagonist.

Despite not knowing how this drama ends yet (Feb 2nd 2020), it reminds me a lot of Healer and the way the relationships formed there.
With both shows, you are on the edge of your seat waiting desperately to find out what is going to happen. Healer involves more flashbacks, and they are needed for the sake understanding the plot, so if you don't like flashbacks, maybe not for you - but I would give it a shot just to experience the chemistry between two amazing actors.
The emotional experience is also similar - you can find yourself laughing one minute, and sobbing the next.

Same writer and has Kim Mi Kyung (healer ahjumma) playing a cop. She likes kimbap in this one too. There’s mental illness in both dramas.

Both: The female lead is a journalist, male lead is after a secret involving a special loved person and there is a conspiracy behind the secret. Action and business related too.

This may be too soon to say, but the trailer for Broker reminded me of Healer. I think it will have the same vibe. The male leads have similar jobs and approach the female leads for ulterior motives but end up falling in love with her and genuinely wanting to protect her.

Both dramas has lot of action
Healer has more romance
SL is hidden gem filled with plenty funny moments, which will make you burst in laugh

Zhang Jing Yi is the FL in both. The chemistry is natural. The relationship had depth. However, BEITD does not have a satisfactory ending.

The setting and atmosphere of two dramas are alike. Both contains action scenes and involved large company frauds. In "Healer", the male lead hides his real identity and pretend as someone to get the job done. In "Are You Human Too", a robot pretends to be the chaebol who is in a comatose to save his inheritance. Both use likely high technology equipment / gadgets in their mission.

Although healer isn’t set in the blue house, in both dramas there is a big Powerful secret organization that basically runs everything that needs to be takin down....

Both have bumbling and clumsy male leads that lead a double life. Except in Extracurricular, he's not faking it.

Similarities :
1. Same genre. I.e. Romance and action
2. Male lead is a a fighter and very protective of the female lead.
3. Both the female leads are innocent and naive creatures who accidently got caught up in bad situations.
4. The leads meet each other when the male lead is on the bad side group.

Differences :
1. Healer is korean and mysterious love is chinese.
2. Healer is kinda like one man army while ML is more like I got all my brothers and me.
3. Different professions
4. Healer has more of childhood past while ML has more of 5yrs ago past.

There is more but this is main
I am sure you will like both.

this is more comedy, but I would say the romance part is really worth swooning... A one sided love that starts from childhood that he chases her till adulthood... It's more of a noona romance but the Chemistry is a big surprise!.. There's also, action and mystery.. And a great OST's as well... Very fun to watch!..

Both shows have Yoo Jitae in them, got the same vibe and very similiar main characters (vigilante lead, journalist helping him, antagonist trying to stop him etc.)

If you want some more mystery and thrill, Healer has it too.... Thou it's outside school but, romance is over the roof!!.. Combined with action and comedy..... Great OST's too.... It's enjoyable to watch...