What is the reason for lower latency in 4G/5G than in 2G/3G?
Mainly because of lesser number of nodes…No BSC, RNC.
On Air Interface you also have smaller TTI/Slot duration (assuming SCS 30kHz and above), which will reduce your latency, specially in FR2.
In addition to what was mentioned by colleagues, there are the following points:
Slicing which consists of cutting a 5G network into slices and each slice will be dedicated to a well-defined use;
Cloud RAN or CRAN;
Use of LDPC codes.