Wi-Fi 6 (802.11ax) is the current generation of wireless networking, succeeding Wi-Fi 5 (802.11ac). It offers higher top speeds, but its real-world benefit is handling many connected devices at once more efficiently -- useful in busy homes, offices, or cafes.
A laptop with Wi-Fi 6 will make the most of a modern router; on an older router it still works fine, falling back to the older standard it supports.