Verizon has started generating 5G service, surprising many in the industry as its launch date had been set from about a week from now. On the other hand, it is only available in either Chicago or Minneapolis, and in restricted areas of these 2 cities. Nevertheless, it means that the Moto Z3 is technically the world's first 5G phone.
https://www.notebookcheck.net/Verizon-unexpectedly-launches-its-5G-network-making-the-Samsung-Galaxy-S10-the-world-s-second-5G-phone.415808.0.html