Was the cat real? Or CGI? If real, how did they train the cat?

You don't think cats can be trained because your cat hasn't been trained?

Can was so distracting. I hated it.

Biggest diva ever was that cat. Word is she had unlimited helpings of Fancy Feast written into her contract.

A lot of animals can be trained and are big part of the movie industry. They even have animals trained to do very specific actions.

Maybe a mix? At times it looked real, at others it was a bit uncanny valley level.

I think for the most part the cat was real.

Although not easily, cats can be trained. My cat would walk on a leash.
You have to convince the cat that it wants to do what you want it to do.

From wikipedia it seems they're claiming it was all real.

Paramount executives wanted Frodo to be computer-generated, but Sarnoski's insistence for a real cat changed their minds. Frodo was played by two cats named Nico and Schnitzel. The script originally depicted Frodo as hissing and arching its back, a natural reaction to feeling threatened, which animal handlers could not train the cats to do; to avoid scaring the cats or using CGI, those elements were removed.