VideoCardz.com posted a story that Intel has confirmed the existence of Z390 & X399 chipsets
A quote from the article:
Intel has confirmed the existence of Z390 PCH The Z390 and the rest of 300-series chipsets will support Coffee Lake (CFL) and Cannon Lake (CNL) CPUs, according to Intel document. The document also revealed Cannon Lake and Coffee Lake series (HEDT) designed for X399 chipset. Intel was expected to skip this codename as it was already taken by AMD for the first-generation Threadripper.Intel confirms Z390 & X399 chipsets