All Features will be listed at this link
Named arguments are the first feature listed on the php 8.0 announcement page. These arguments now allow for optional parameters, meaning that you do not have to list out every single variable. The arguments are also order-independent and self-documented.
Instead of creating a bunch of if-null statements to check for nulls, you can now chain all the variables together in the same line, and it will check for all the nulls in the order of the chain.
Down near the bottom of the page, there is a large section talking about Just-In-Time Compilation. This is reportedly said to increase performance on various sites and applications by 400%, quite the vast improvement, across the board.
In Summary, PHP 8 offers a wide range of new features to work with, including but not limited to: Named Arguments, which allow for optional parameters and a wider range of options, Nullsafe operators, which makes handling nulls quicker and easier, and Just-In-Time Compilation, which should increase performance for those using PHP across the board.