According to a leak roadmap presented by Intel at the Chinese University of Changsha City, The Ice Lake scalable processors were pushed to 2020 due to some 10 nm fabrication process issues. Meanwhile, Intel will launch the Copper Lake scalable Xeon CPUs a few months before the Ice Lake family. The roadmap also shows the 28-core Cascade Lake HPC CPU scheduled for an early 2019 release.
https://www.notebookcheck.net/Intel-s-Scalable-Xeon-CPUs-to-arrive-by-2020.318350.0.html