AMD could be readying the Ryzen 4000 lineup and the X670 chipset for a late 2020 launch, according to a report from MyDrivers. Ryzen 4000 is expected to feature good IPC improvements and slightly higher clocks than the current Zen 2 lineup. Also being speculated is that Zen 3 will be the last of the Socket AM4 processors as Zen 4 will likely make the transition to Socket AM5 keeping in mind developments with respect to DDR5 and PCIe Gen5.
https://www.notebookcheck.net/Ryzen-4000-and-X670-to-launch-in-late-2020-Socket-AM5-to-debut-with-Ryzen-5000.446653.0.html