Disclosure: I work on Google Cloud.
NVMe is (now) a more general purpose "speak to flash like things". This Optane memory stuff is made of "flash", but unlike our Local SSD offering (or AWS's i3) it's at a latency and throughput closer to DRAM.
Despite it being marketing material, I find the pyramid diagram [1] helpful. This blog post is about "Optane Persistent Memory".
[1] https://newsroom.intel.com/wp-content/uploads/sites/11/2018/...