The latest mobile technology is being introduced with a worldwide standard of 3GPP NR for use with the higher millimetre-wave (mmWave) RF frequencies. America has been one of the first countries to heavily adopt this in the ranges of 24GHz and 28GHz (which is currently being auctioned off). Other countries are starting to auction off the higher frequencies throughout 2019 with a larger deployment for consumers in 2020.
FierceWireless.com has started to map out the cities that have adopted 5G. These are by telco carriers, AT&T and Verizon and in cities such as Sacramento.