Source: https://www.reddit.com/u/headin2sound/

TL;DR: This is not a DLC. This is Cyberpunk 2.0.

• virtually every system of the main game has been changed and/or updated
• police system is completely reworked with multiple tiers of NCPD/mercs chasing you down in vehicles according to your wanted level, apparently on level 5 maxtac will chase you down and it will be some sort of bossfight against them (source: https://www.youtube.com/watch?v=riK1i8lQwRM&t=511s)
• perks and skills have been completely overhauled, no longer simple passive stat boosts, much more active abilities like different melee finishers, a dash, or the ability to deflect bullets with melee weapons
• an entirely new 6th skill tree that uses a different type of skill points (relic points) that will be used to add new abilities to your cyberware
• the difficulty curve is reworked/rebalanced
• the loot tiers are reworked
• archetypes of enemies have been redone for more variety in combat encounters
• installing cyberware now has an effect on your body and you cant install too much or else you will go cyberpsycho (no idea what that looks like in game)
• installing cyberware now has a first person cutscene added to it, just like in the prologue at Vik's clinic
• you can now "attune" cyberware to one of your attributes, making it more efficient if you have invested in that attribute; example here optical camo is attuned to the "cool" attribute: https://i.imgur.com/1UI9SEX.png
• armor is no longer tied to clothing, it is instead tied to your cybernetics
• vehicle combat is added to the game, you can even use your katana on your bike
• you will be able to hack vehicles, similar to the Watch Dogs games
• vehicles are no longer bought from fixers, but bought through a website set up by wakako
• some vehicles have guns installed on them (machine guns, rocket launchers)
• new type of infinitely replayable/repeatable missions are being added where you need to steal certain vehicles marked on your map
• new activity introduced "airdrops", loot caches that drop randomly on the map that you can fight over and retrieve for yourself
• tons of new random events/activities are added to make the world feel more alive, like car chases and gang fights