Many people (including possibly most film scholars) believe that film noir as such ended in the late 50s. Touch of Evil in 1958 is often cited as the last major true film noir.
Personally I’m inclined to see 1967 as the watershed year. That year saw the fateful release of Bonnie and Clyde. OK, it’s not film noir or even neo-noir but it did change the rules of crime movies. After Bonnie and Clyde the crime movie would rely on violence and action. Film noir by its very nature is character-driven, and (perhaps to an even greater extent) mood-driven. After 1967 film noir could not really exist.
That’s not to say that there haven’t been some interesting neo-noirs that have emphasised character and mood (Chinatown and Body Heat for example), but as a general rule the post-1967 movie world has not been a world in which film noir can flourish.
The noirish movies of the early to mid 60s, even those (like Godard’s and Truffaut’s) that were intentionally revisionist, are still essentially noir.
For me the real end point for noir was Point Blank, which was also released in the fateful year of 1967.
That’s just my personal feeling of course. What do others think?