The usual reminder: REAL 4G arrives with LTE-Advanced
Anything called '4G' that isn't LTE-Advanced is not actually 4G. Instead, it's merely a marketing ploy to sell high end 3G technology.
"5G" is similarly an act of imagination, not actually having any agreed upon specification. Meanwhile, it took many years for real 4G to be deployed after the spec and sample hardware were available. Real 4G still hasn't been deployed in the majority of the world. It's of course going to take several more years before we see real '5G' deployed.