Ah, a bugaboo of mine.
I ALWAYS sell my next game by tipping my hand on the setting, adventure path, or both, so that my players know way in advance what to expect.
I did a pirate campaign in Eberron. I got Eberron PCs with a nautical theme
I did a Ravenloft campaign: I got tortured heroes and cursed adventurers
I plan on doing Wild Beyond the Witchlight and I'm getting ideas for fey-or-whimsical PCs.
My group is good like that, mainly. I DO have one player who will directly go against type or find some strange thing to do their own way. But we humor his eccentricies and then ignore them.