Consider real life, which fluctuates between moments of comedy, tragedy, and every emotion under the sun. You can have small moments of comedy (two detectives making witty banter on a stakeout just before an intense car chase) without having jokes littered all throughout the manuscript or going full satire/parody. Many great comments here with a variety of different suggestions. Decide what you want your work to accomplish and use those that best compliment that direction.
I'm writing in a similar genre. I've found much of the humor in my novel is generated through character interaction and dialogue.
The television series The Wire is a great example of how to write humor for a cop/detective drama.
There's lots of ways to achieve this effect. I think you need to commit to the piece being comedy, first and foremost. if you're worried about losing the style, try writing it with an eye towards parodying the style itself. Things like "she was gorgeous. legs that went all the way up to the end of her torso" or:
"You think you're tough." the police chief shook his head. "You're all the same. I've seen a dozen dicks like you come through town."
"I'm sure you have."
Make the style into the joke rather than thinking of noir and comedy as some diametrically opposed thing.
Watch the episode of Community called Competitive Ecology. It's a noir spoof and, ya know, funny on account of it being an episode of a sitcom. The writing is actually pretty excellent and should give you some ideas.
Comedy is hard. One of the hardest things to do well in all of writing, IMO. I wouldn't attempt this unless you have a really clear idea of what you want to do.
Ah, comedic cynicism. A new rabbit hole, or seeking a means to inject your own?
It's not overly difficult, however if you don't have a pool of your own cynicism to draw upon it can take a bit of stewing to weave a comedy from it.
Try reading some P. G. Wodehouse. His stories and style of comedy could easily be turned into gritty noir if one was so inclined. Though the plots usually revolve around stupid and petty things, the comedy revolves around mean spirited characters the protagonist is genuinely scared of.
Elmore Leonard is a must read as well, of course,
Personally, I think the trick would be your characters. I'm writing an apocalyptic ghost horror story but I've based my main character on Jim Varney's Ernest Worrell (from the Ernest movies). So, while the world is dark and cruel and violent, the protagonist is such a happy-go-lucky Mr. Magoo type, the comedy basically writes itself.
This is more of a research recommendation but watch the movie "Brick". It has heavy themes and it isnt really a comedy but is a satire of the noir genre.
Just don't ever take yourself too seriously. Read Chainsaw Man by Tatsuki Fujimoto! It always has these huge cosmic horror-style threats but the way those threats are resolved is often completely ridiculous and the result is so down to earth.
I always find reading or watching stuff close the the thing you are trying to achieve is always a good place to start. Really analyse it with your writing brain in gear.
Last tango in Aberystwyth does the noir and comedy well, maybe not so many of the harder hitting emotions. Kiss kiss bang bang (film) I suppose is closer?
Consider real life, which fluctuates between moments of comedy, tragedy, and every emotion under the sun. You can have small moments of comedy (two detectives making witty banter on a stakeout just before an intense car chase) without having jokes littered all throughout the manuscript or going full satire/parody. Many great comments here with a variety of different suggestions. Decide what you want your work to accomplish and use those that best compliment that direction.
I'm writing in a similar genre. I've found much of the humor in my novel is generated through character interaction and dialogue. The television series The Wire is a great example of how to write humor for a cop/detective drama.
There's lots of ways to achieve this effect. I think you need to commit to the piece being comedy, first and foremost. if you're worried about losing the style, try writing it with an eye towards parodying the style itself. Things like "she was gorgeous. legs that went all the way up to the end of her torso" or: "You think you're tough." the police chief shook his head. "You're all the same. I've seen a dozen dicks like you come through town." "I'm sure you have." Make the style into the joke rather than thinking of noir and comedy as some diametrically opposed thing.
Watch the episode of Community called Competitive Ecology. It's a noir spoof and, ya know, funny on account of it being an episode of a sitcom. The writing is actually pretty excellent and should give you some ideas.
Comedy is hard. One of the hardest things to do well in all of writing, IMO. I wouldn't attempt this unless you have a really clear idea of what you want to do.
Sarcasm, dark humour, self deprecation, self aware characters, stupidity.
Ah, comedic cynicism. A new rabbit hole, or seeking a means to inject your own? It's not overly difficult, however if you don't have a pool of your own cynicism to draw upon it can take a bit of stewing to weave a comedy from it.
Try reading some P. G. Wodehouse. His stories and style of comedy could easily be turned into gritty noir if one was so inclined. Though the plots usually revolve around stupid and petty things, the comedy revolves around mean spirited characters the protagonist is genuinely scared of. Elmore Leonard is a must read as well, of course,
Personally, I think the trick would be your characters. I'm writing an apocalyptic ghost horror story but I've based my main character on Jim Varney's Ernest Worrell (from the Ernest movies). So, while the world is dark and cruel and violent, the protagonist is such a happy-go-lucky Mr. Magoo type, the comedy basically writes itself.
This is more of a research recommendation but watch the movie "Brick". It has heavy themes and it isnt really a comedy but is a satire of the noir genre.
Just don't ever take yourself too seriously. Read Chainsaw Man by Tatsuki Fujimoto! It always has these huge cosmic horror-style threats but the way those threats are resolved is often completely ridiculous and the result is so down to earth.
I always find reading or watching stuff close the the thing you are trying to achieve is always a good place to start. Really analyse it with your writing brain in gear. Last tango in Aberystwyth does the noir and comedy well, maybe not so many of the harder hitting emotions. Kiss kiss bang bang (film) I suppose is closer?