The typical latency difference between existing 4G and new 5G is about 10-15 ms. 5G latency in 2019 is ~30 ms in independent tests in the US, Korea, and England. The latency is about the same in the other two dozen 5G deployments in 2019. That's what 5G equipment is designed for.
The chart is based on Open Signal data from Germany early in 2019. In LTE, Vodafone had 40 ms latency and Deutsche Telekom 42 ms. That's higher than the 30 ms typical of 5G, but not wildly so. Very few applications will be affected.
Latency on LTE networks will continue to fall as older equipment is replaced. New LTE equipment from Ericsson & Huawei brings air latency down to ~13 ms, only 3 ms more than today's 5G.
Latency will be reduced in many locations with Edge Networks (all of China) and/or improved backhaul/transport. (Verizon is doing both over the next few years.)
4G latency tests around the globe generally produce results between 35 and 55 ms. One LTE test at Verizon showed 23 ms and more than 55 ms is not uncommon.
1 ms latency is a myth outside the labs for years.