Intel's mainstream desktop chipset for the overclocking crowd hasn't changed much in the two generations since Z170 entered the market alongside the company's Skylake chips in mid-2015. The big addition with Z270 was support for the manufacturer's Optane cache modules, and Z370 didn't seem to be much different aside from some changes regarding power delivery for the accompanying six-core Coffee Lake processors. The release notes for the latest version of Intel's Rapid Storage Technology drivers hint at Z390 and X399, two future chipsets that could potentially offer new features.
Screen capture from Intel driver release notes
Past numbering conventions suggest that the X399 chipset will be meant for use with high-end desktop Core X chips with 2000 or more pins. The intent of the Z390 chipset is less certain, since Intel hasn't released any Zx90-labeled chipset in the recent past. We suspect it will be a new top-end offering for use with mainstream desktop CPU, possibly rumored eight-core models.
We still don't know if either of these future chipsets will bring the integrated USB 3.1 Gen 2 or Thunderbolt 3 support that some users have been hoping for. A safer bet is the inclusion of the semi-integrated 802.11ac Wi-Fi and Bluetooth found in Intel's H310, B360, and H370 desktop chipsets. The driver release notes provide no data regarding potential release dates for motherboards with the Z390 or X399 chipsets.