AMD reports that the new architecture for the Zen 2 are already ready, based on 7nm, although the manufacturing process is still a bit green and until 2019, they will not reach the market.
The Director of Technology of AMD, Mark Papermaster, has announced that they have already completed the design of the Zen 2 architecture. This new architecture will be implemented within the third generation of Ryzen processors, which should reach the market sometime time of 2019. Before these processors, the company plans to launch the new second generation processors, which are based on Zen +, an update of the current 14nm Zen, but in this case they will be manufactured in 12nm.
The third generation of processors will not hit the market until 2019, when the Ryzen based on Zen 2 will be launched, which will be based on the 7nm manufacturing process. It should be noted that x89 processors have greater complexity in terms of development than other systems, such as ARM. These x86s will be manufactured in 7nm, but it is still early, the process is still a bit green and that will force TSMC and GlobalFoundries to improve the manufacturing process, something that does not aim to be easy. It may be until mid-2019, when the new Zen 2-based processors arrive.
Zen 2 is a big improvement over the current Zen cores, in many details, according to AMD, but not much more detail has been given either. It may take a while for more data to be released regarding these processors, we may not know anything more about them until the end of the year. It should be noted that the AM4 socket will remain valid until 2020, so on a current motherboard, any compatible processor can be installed, you will only have to install a BIOS update and enjoy.
Source: Fudzilla

I would like them to have an improvement in the ipc and the infinity fabric