Wi-Fi 6 is a next-generation wireless technology which was previously known as 802.11 ax, but later on, the Wi-Fi Alliance decided to change the name and gave it a more handy name. Wi-Fi 6 is superior to the Wi-Fi 5 in most ways. Wi-Fi 5 is used in current routers and other internet devices.

Source:- Wi-Fi 6 Launch Date and Specifications