HardOCP published a story that AMD is preparing 7nm Zen 2 CPUs sampling this year for 2019 volume launch A quote from the article:

Comments made by Lisa Su during a recent earnings call suggest that 7nm Zen 2 CPUs will not fall victim to a paper launch and see wide availability next year, as sampling has already begun. AMD has tasked both TSMC and GLOBALFOUNDRIES for their 7nm lineup, which will include samples of a 7nm GPU based on Vega and 7nm server CPU later this year.

"We have a 7nm GPU based on Vega that we'll sample later this year. We have a 7nm server CPU that we'll sample later this year. And then, obviously, we have a number of products that are planned for 2019 as well. So it's a very, very busy product season for us. But we're pleased with the sort of the execution on the product roadmap," Dr. Su said.

 AMD 7nm Zen 2 CPUs Sampling This Year for 2019 Volume Launch