Killer and Healer

Same republican era drama with same setting and conflicts between the male leads
the friendship is the main story in killer and healer of course not the romance

Very sophisticated emphasis on fathering, mental health and trauma among the male characters and demonstrates how care - both collective and individual is the path to healing

Gu Yan Shan and Ding Yi, despite undergoing temptations and risky situations that could get them saved by selling out one another, none of them betray the other. Gu Yan Shan promises to protect Ding Yi, he does so even when Ding Yi defects to the communist party and start working secretly for them.

Police officer Pang Hong Mei amid the many obstacles created by U.S. and Jiang spy agents, rescued Ji Danyang, a patriotic scientist who returned from the United States from the enemy spy. She accompanied Ji Danyang to Lumen City to participate in the "Water Drop Project". Enemy special forces formulated a sabotage plan codenamed "Operation Rock" and concentrated their forces and tried to destroy the "Water Drop Project." Pang Hongmei and Ji Dan Yang fought a life-and-death battle with enemy agents in Lumen, thwarted the enemy's conspiracy, protected the "Water Drop Project" and finally achieved the expected success. The couple who went through the test of life and death, also realized their dreams and firm ideals.

This is also set in the Chinese republican era with almost the same sets and styles. They all fight to survive

Both dramas are set in the Chinese Republican Era. While Detective L has comedy, Killer and Healer is more serious themed and has a censored romance between two male leads.

A story that follows two men who are polar opposites; one kills while the other heals. One is a violent cop, and the other is a compassionate doctor. Together, they support and redeem each other during troubled times. Jiang Yue Lou heads the Jingcheng Police Station and appears neither good nor evil. Yet smugglers tremble at the thought of him.

While investigating an opium case in Hong Kong, Yue Lou encounters Yu Zhi, who learns that Yue Lou suffers from bipolar disorder. Although initially reluctant to undergo treatment, Yue Lou eventually opens up to Yu Zhi. Despite their differing values, they slowly become close friends. At this time, the secrets from the past start to bubble to the surface.

Both drama have Strong Bromance story
Both dramas have the same main lead actor
Both are from the same shitty channel Mango who doesn't care about it's dramas

Both dramas have Two friends who fought gangsters and police corruption
they tried to protect and save each other from the cases they are involved in
The korean drama has more fight scenes and side romantic story
not sure about the chinese one yet

Both are bromance/Bl themed dramas with one of the lead character being a cop and the other a doctor.

Both are kind of similar. ..both includes police investigation theme, crime solving duo, perfect chemistry between both male leads and we can see bromance in both drama....

The main leads are polar opposites. Both main leads in "Killer and Healer" and "The Sign" have opposite personalities that complement each other well.

Both republican era dramas
Both have struggles in desperate times
Both are fighting to protect their country and keeping it safe in chaos and war
killing people is the most common theme and it shows How turbulent time it was

Similar themes of Republican Era, class struggle, coming to class consciousness, westernised/western educated elites becoming traitors to their class, revolutionary war, intertwined with family, brotherhood and love

Both have crime, action and two male leads and no female lead.
Both guys in under the skin are detectives.
Both guys are there for one another in under the skin too.
Not a lot of bromance in under the skin as compared to Killer and healer but still, good enough and the plot is good too.