The villain was CGI, but essentially everything else in the film was done with old school effects and actual filming locations.

Compare this to many, many modern movies where the stage is basically the size of oh about a basketball court and is surrounded by either green screens or high res displays with a few props, where the situation is essentially the inverse of T2: the only real thing is the actor and nearly everything else is CGI.

Hell even a lot of the shots of the wounded T1000 were done with sculpted mannequins and prosthetics and such.

Even in a what is probably the best current modern action movie series of John Wick, (though I have yet to see 4 so maybe this has changed) basically my only real gripe with it is that it uses CGI blood in action sequences instead of squibs.