Here's why David Caruso retired from acting after CSI: Miami - and if he might ever cameo in CSI: Vegas. After starting his career with small roles on TV shows like Hill Street Blues, Caruso went on to become a working character actor during the '80s. He had supporting roles in 1982's First Blood - where Stallone nearly wasn't cast - Twins and Abel Ferrara's cult crime thriller King Of New York. Caruso's steely intensity was put to great effect when he was cast in cop show NYPD Blue as Detective John Kelly. Even among a great cast, Caruso was the standout, but famously, the actor let the attention and praise he received go to his head.
With aspirations on becoming a movie star and with his behind-the-scenes behavior alienating cast and crew, he was dropped from NYPD Blue four episodes into its second season. His designs on becoming a major star didn't work either, with erotic thriller Jade and neo-noir Kiss Of Death - which received solid reviews - both bombing. Caruso's career was left somewhat in limbo during this period, though he made a big comeback when he signed on to play Horatio Caine in the spin-off CSI: Miami.
First introduced during a crossover episode with CSI, Caruso quickly made the role of Caine his own. The character was a former bomb squad officer and homicide detective who headed up the CSI crime lab in Miami. The show provided Caruso with an unexpected comeback and he became an early meme for his tendency to dramatically put on his sunglasses after making a bad pun. The actor went on to appear in every episode of CSI: Miami's ten seasons, but while the show was incredibly popular during its run, it notably didn't receive a series finale. The show was canceled due to dipping ratings and raising production costs, and in the aftermath of its ending, David Caruso retired from acting.
Caruso didn't make any kind of announcement about retiring either, and after CSI: Miami - which killed supporting character Speed in season 3 - finished, he moved into the art business and opened a gallery in California. That gallery later closed in the late 2010s and Caruso no longer appears to be involved with the art world. Considering Caruso's time playing Caine was quite lucrative, he likely decided to retire on a career highlight and explore other interests.
Since CSI: Miami didn't have a proper ending, there's still room for the latest franchise outing CSI: Vegas to offer some closure on Caine. That said, David Caruso appears happily retired and out of the business, so a guest appearance or return to a full-time TV series is doubtful. It should be noted that William Petersen - who plays Gil Grissom on the show - hadn't appeared in a movie or TV show for about six years before coming back for Vegas' first season, so a Caruso comeback may not be totally out of the question.