The Fiery Priest (2019)

They have a similar vibe. The same type of humour and elements of crime investigation even if the storyline is totally different.

No romance but still perfect chemistry
The story is deep and catchy.
Both male lead and female lead team up to find the serial killer,murders and also the person who murdered them
Hooks you up till last ep

If you are missing Fiery Priest already, have a little stop-over in One The Woman. Everyone is still patiently waiting for TFP 2, but One The Woman looks like a spin-off with Lee Ha Nee's character in focus.
I swear, if you loved Le Ha Nee's role as a prosecutor, you will definitely be satisfied with One The Woman focusing on the female prosecutor's story.

Backstreet Rookie[3] (Korean: ??? ???) is a 2020 South Korean television series starring Ji Chang-wook and Kim Yoo-jung. It is based on the 2016–2017 webtoon Convenience Store Saet-byul written by Hwalhwasan.[4][5] It is the first Korean drama funded by the global channel Lifetime and produced by Taewon Entertainment.[6] The series aired on SBS TV at 22:00 (KST) time slot from June 19 to August 8, 2020, on Fridays and Saturdays for 16 episodes. It is available on iQIYI and on Rakuten Viki with subtitles in multiple languages globally.[7][8]

Both have:

- a male lead and his team, which are often beaten by the bad guys (often quite literally beaten.. sometimes just beaten).
- an unconventional catolic priest in it which claims that the bad guys must "burn in the fiery pit" and fight them with actual fights (and weapons) and not words; while writes or recites texts of the Bible;
- a charismatic female cop whom becomes the male lead's sidekick;
- a corrupt female prosecutor whom seems to have the hots for the good guy, while being probably liked by/and working for the bad guys..;
- corruption and stupidly within the police force and prosecution;
- a harismatic male psychopath as the main villain.

For a good balance between comedy and crime/suspense that is maintained well throughout the entire series.

1- both ML have been well trained agents
2-it starts the same ( drama started with how they got into fighting the bad
3-both ML have slightly romance with FL
4-in both dramas are ML working with other leads like a squad

Although its different in terms of genre and plot, it's similar towards Hwi Oh's side of the story

- The ML has similar problems; mental illness, anger issues, ptsd...
- ML works with the police to solve justice on a supposedly closed case
- both are comedy, except MFEO is a bid more sad and undertoned

Both are action,comedy genre (at the most serious moments/scenes it can make you smile.
Both male leads are after justice and can’t stand injustice ,their facial expressions are so good and are so funny to me.
Just like in The Fiery priest Kim namgil’s character is way different from the priests we’ve seen before ,in Bad prosecutor Do Kyungsoo’s character is different from the prosecutors we’ve seen before

Both of the main leads in the dramas deal with the loss of their loved ones and try to fight against the people with power and uncover the corrupt system.

Both MLs are motivated by revenge.
No romance
Both fighting corruption.
Both have strong ladies supporting them.

Similar plot with the main characters being involved in a huge mystery surrounding the death of someone close to them, and both the ml's have a tragic past that led them to their current profession. A lot of the comedy gives off the same vibe. Overall, both are great shows.

Similar characters, similar suspense in storyline, even similar way of storytelling and most importantly - the chemistry between the leads, great fighting each other, even greater fighting together. Overall same vibe

They have a similar set up and consist both of a man who wants to avenge a death in taking an organisation/corrupt city officials down.

I know the two dramas are very different, but I am recommending Queen Seon Deok to Fiery Priest fans because Kim Nam Gil's role as Bidam in Queen Seon Deok is simply unforgettable. Kim Nam Gil's shows both comedic and serious acting that eventually gave him his best new actor nomination at baeksang for Queen Seon Deok. He first appears in Episode 21 or 22. But I still recommend people to watch the whole drama since the whole drama is epic.
For Queen Seon Deok fans, Fiery Priest is a drama where Kim Nam Gil is the main character (you don't have to wait more than 20 episodes for him to appear). You can guarantee he gives great performance in Fiery Priest, he was after all nominated for another baeksang award for this role, he won daesang at SBS awards as well.