PCI-SIG has completed work on Revision 0.3 of the spec, which means PCI Express 6.0 is now on track to be finalized in 2021; assuming the group does not hit any major roadblocks before then. For the unaware, PCI-E 6.0 will bring data rates of 64 GT/s (twice as fast as PCI-E 5.0's 32 GT/s), while "maintaining backward compatibility" with all previous generations of the tech.
According to PCI-SIG, the two key new features of PCI-E 6.0 will be PAM-4 encoding (Pulse Amplitude Modulation with 4 levels), and "low-latency Forward Error Correction," which should help to boost "bandwidth efficiency." In other words, 6.0 is (predictably) set to be the fastest PCI-E specification to date.
Unfortunately, that might not mean much for the average PC user. As many of our readers are likely aware, the PCI-E 5.0 specification has yet to be implemented into any actual consumer motherboards, and even the PCI-E 4.0 spec isn't widely supported yet (though that's changing).
Regardless, PCI-SIG has encouraged its member companies to offer input on, or otherwise contribute to the PCI-E 6.0 specification moving forward.