[Curious Question] How does lichess actually detect cheaters ?

Is having 0 inaccuarcies, 0 mistakes, 0 blunders and very low centipawn loss. Is that all ?

Doesn't all this depend on other player playing ?

(or)
Is there some A.I to detect cheaters in lichess ?

(or)
Is it some human intution to detect cheaters ? [ I mean like report and stuff]

I have seen that lichess uses only stockfish9+, what-if some one uses fritz,chess.com analysis, houdini, komodo, find the next best move chess, rbkya (or) Leela chess zero etc. How can you detect them ?

github.com/clarkerubber/irwin

Modern AI resemble self-learning „expert systems“.

Read this:

www.reddit.com/r/chess/comments/9s9ml8/how_does_chesscom_and_lichess_deal_with_gms/e8n9uwg

...
„Instead these systems are based more on probability. Big websites have millions of games to analyse - including games with confirmed GMs to learn from. A fraud detection algorithm can consider unlimited questions like:

If black has a 3 pawn lead but lots of unguarded pieces and down a knight, how likely are they to aggressively recapture instead of defend?
If black has been playing aggressively, how likely are they to play a very difficult to calculate defensive move?
When black has 15 available moves, 10 of which are pretty good, how long will it take for black to play a move?
Black has played 20 straight GM level moves and has a strong material lead. What are the odds that black will now play an amateur blunder? A "look I'm not cheating" move?
Is black suddenly playing like a GM whenever there's one really important move?
Does black suddenly play very well mid game if they are slightly behind? How likely is a human to do that?
Is black playing hard to calculate moves just as fast as easy to calculate recaptures?“ ...

Arguably even intelligence from 1900 could answer some of those questions. I recommend reading the entirety of en.wikipedia.org/wiki/Chi-squared_test to get a sense of how useless ACPL is compared to actual science.

Some of these questions seem incredibly complex for an AI.

In particular "Playing aggressively" and "Difficult to calculate" - how do you define these?

The AI creates definitions for itself. It „sees“ interactions which humans don’t see. At least „expert systems“ do that. -> data mining