In general, what's your strategy when facing 3bets OPPO with KKds? Like KcKs5c3s

Say it's fairly early in a session,
Hero pots utg to 3.5bb, btn pots to 12bb,blinds fold back to us. What do you do vs....
1.A weaker passive player who's limped several hands pre and this is 1st or 2nd 3bet
2.an aggressive player who's 3bet several times in under 100 hands so far, say 4+ times
3.a nit

I'll share my thoughts after gettimy opinions of others