Intel is ever-so-close to releasing its new flagship Core i9-9900K processor, the first 8C/16T processor from the company, and it will launch with the new Z390-series motherboards that we're beginning to see more and more of.
The company will be launching three new 9000-series parts in the coming weeks, with the Core i9-9900K, Core i7-9700K, and Core i5-9600K that will all work on existing Z300-series motherboards, as well as the upcoming Z390 boards that will launch with the new CPUs. If you want to overclock the hell out of these next-gen K-series parts, you'll need the Z370 or Z390 motherboards to squeeze all that you can from the Coffee Lake refresh.
Intel is expected to unveil the new 9000-series processors next month with a joint launch of the Z390 family of boards.