i5-6500 will fit in the following chipsets: B150, B250, H110, H170, H270, Z170, Z270
There isn't much point in looking at future upgrades if you have that chip to work with. While LGA1151 is the socket type for Z370 (and I suppose now Z390, B360, and B310) they re-wired the pins so they aren't backwards compatible.
If you bought any 200 series board now, in the future you could drop in an i7-7700k.