Forget the disappointing end to Line Of Duty, the best cop show on TV has got to be BOSCH on Amazon Prime - absolutely superb.
I’ve also been working my way through the original books by Michael Connelly, which are great page turners, but the TV series is something else.
Watch it, you won’t be disappointed.
The only BOSCH I can find is on bbc ?
Well, historically, the best cop shows I ever watched were NYPD Blue and Hill Street Blues. Both were cutting edge, and probably stand up to scrutiny now. NYPD Blue had an ex homicide detective on board as a producer, and he provided a lot of the, true, storylines, Bill Clark was his name if my memory serves me well. Dennis Franz, now retired, starred in both shows and brought NYPD Blue to life, if you’ve never seen It, you really ought to. The great Steven Bochco wrote and produced on both shows, sadly passed away in 2018…
You don’t seem to have mentioned Miami Vice? 
The Thin Blue Line 
My cousin was in the police when this was on TV , we always used to say he was like PC Goody .
Bosch is good, not quite a cop show though similar genre, Goliath on prime is also worth a watch.
I find a lot of Italian & Scandinavian crime box sets & series knock UK PC corrected stuff into the weeds.
The Bridge, Ice Cold Murders etc. Dark, cerebral, sometimes brutal, and lots of bodies on slabs. Lovely.
Currently on BBC IPlayer " Those who Kill" has my current attention. Ch4 is a good source but youneed to give the robbing swines 4 quid a month to dodge the ads. But it’s worth it if you can abide sub titles.
Just make sure you have had dinner.
Life on Mars.
Prime Video.
Because he’s a Grown-Up?!!
I would agree with sdg111 regarding NYPD. It was noted for it realistic portrayal of police life, at the time, in the Big Apple. Although it would seem tame by today’s standards at the time the first series was aired in the states it was broadcast with a warning about the contents. Denis Franz was the lead, with David Carruso having left at the end of the first season. Franz went on to win four Emmys, the show won twenty prime time Emmys. It is considered by most critics to have set the standard which has lead to shows like the Wire and many others. If you can watch it I would certainly recommend it.
PS you can probably tell I was/am fan……
‘No Activity’ for me, the original’Stan’ Aussie cop comedy!
Aired on BBC 2 couple of years ago, then on I player. Vanished for a while, then I paid for download on Amazon Prime series 1 and 2
It’s probably cult viewing but I find it hilarious!
Search for ‘million buses sketch’ on tinterweb
If you’ve not watched Money Heist you don’t know what your missing
Is it me, or do Prime & Netflix criminal stuffs not taste quite the same without Pringles & Hobnobs & a nice cuppa??
Thin blue line was brilliant! Funny you mention that as we’ve just re-watched Blake’s 7 from back in the 70’s and detective Grim from thin blue line was in it (obviously considerably younger!)
The Thin Blue Line is great, we liked ‘No Offence’ a mix of drama with some comedy inserted here and there. More serious stuff ‘Endeavour’ or ‘George Gently’ are the more recent one’s we like.
Grim is unimpressed with Kray’s apparently lax attitude
You seem to forget, Kray. It’s my ■■■■ on the line, so you’d better pull your finger out!
D.I. Grim (David Haig) in Series 1, Episode 7
Police 5 
Keep em peeled
Another vote for the brilliant Life On Mars.