Technology never stands still, and neither does AMD. Having reasserted itself into the high-end consumer CPU market with Ryzen, AMD will look to keep itself in the discussion by building out its fancy new architecture. AMD has said as much. As to when and how, a leaked roadmap may provide some answers.
TechPowerUp (opens in new tab) found a few interesting slides at Spanish website Informatica Cero (opens in new tab). One of them is a CPU roadmap that runs through 2019. On the desktop, it shows AMD launching "Pinnacle Ridge" as a successor to current Zen-based "Summit Ridge" Zen processors in 2018. In old Intel parlance, Pinnacle Ridge can be considered a tick—a refinement of an existing architecture on a new manufacturing process. This coincides with rumors of AMD moving to a denser 12nm node for its next generation Zen processors, versus 14nm for its current chips.
Looking further down the line, the roadmap shows AMD releasing Zen 2 processors in 2019. These will be based on a new "Matisse" architecture. There is no mention of core count, so it remains to be seen if Zen 2 keep the same 8-core/16-thread design as current Zen processors, or if AMD will shoot for more cores.
Our hunch is the former, which is reinforced with the roadmap showing Matisse working with AM4 motherboards. AMD previously said it wanted to keep Zen relevant for four years, and this would play into that.
In regards to AMD's notebook and desktop APUs, the roadmap shows "Picasso" APUs launching in 2019. These will be based on AMD's current Raven Ridge APUs, which feature Vega 11 graphics and up to 8 Zen threads. Optimizations should make Picasso a bit faster, and probably more power efficient as well.