To take the example of a fair coin toss: what looks like 50/50 odds classically may or may not be 50/50 odds quantum mechanically.

Or in programmer terms: all classical random number generators are deterministic. The question is whether classic random number generators always rely on (a multitude of) underlying quantum random number generators to produce their result. Or whether they just seem random enough to us but would be just as much without any quantum effect.