5G is on the way, probably including a compatible iPhone in 2020. ArsTechnica has a good rundown of the state of the rollout of the superfast network.
The first thing to know about 5G is that it’s a family affair—and a sometimes-dysfunctional one. Wireless carriers can deploy 5G over any of three different ranges of wireless frequencies, and one of them doesn’t work anything like today’s 4G frequencies. That’s also the one behind the most wild-eyed 5G forecasts. Millimeter-wave 5G occupies bands much higher than any used for 4G LTE today—24 gigahertz and up, far above the 2.5 GHz frequency of Sprint, hitherto the highest-frequency band in use by the major US carriers.