I like to think that any professional out there isn't a "one-trick pony" and only does XXXX one way...because there so many variable nowadays that it is impossible for solution to meet all needs. Now if you ask what methods are out there recognized by professionals for tiling say ceramic tile onto a plywood subfloor - some would say, as pointed out, that tiles aren't put onto subfloors but they're put onto 'underlayments', but that's just a minor syntax question.
But once you have established that the floor is suitable for tiling, then one method would be to put down a plywood underlayment, then thinset; or put down a cbu or a cleavage (uncoupling) membrane, then thinset on that; or put down a mortar bed.
Now each of these methods has particularities specific to each method, but those in a nutshell are the methods I can think of, as possibilities.