PCIe Gen 5.0 was implement4ed on Alder lake and the corresponding chipsets like Z690. However, PCIe Gen 5.0 SSDs have not yet arrived. They're expected in 2022, but as a showcase, Intel showed a RAID setup demonstrating they can reach 28 GB/sec throughput with an SSD.

This tech was supposed to be demoed at CES, however with that being canceled  Intel's Twitter account showed some results and photos. Ryan Shrout (who works at Intel these days) has previously demonstrated an Alder Lake system paired with a Samsung server SSD based on the PM1743, that one achieves a throughput of 13.8 GB/s with a PCIe 5.0 plug-in card.. When paired and setup in RAID-0, they breach 28 GB/sec. The Samsung PM1743 SSD is geared at the server sector, not at end users/consumers. However, you may expect the first standalone NVMe PCIe Gen 5.0 SSDs in 2022.