Intel has quietly expanded Optane support to include 8th-gen and above Pentium and Celeron processors. Aside from the 8th-gen requirement (the report at Tom's Hardware lists this as 7th-gen or above, but Intel's release notes specify 8th-gen) users must also be running Rapid Storage Technology (RST) drivers version 17.2 or later, and have a compatible BIOS.
The direct quote from Intel's driver release description:
"Intel® Optane™ memory support extended to desktop Intel® Pentium™ and Intel® Celeron™ processors starting with Intel 8th generation systems and Intel® RST 17.2 driver or later. You must have the corresponding system BIOS for support. Consult your motherboard/system vendor for more information."
The latest driver (Intel Optane Memory User Interface and Driver for System Acceleration) was actually released back on February 20, and is currently version 18.104.22.1689.