Copying this from another comment
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
• the difficulty curve is reworked/rebalanced
• the loot tiers are reworked
• archetypes of enemies have been redone for more variety in combat encounters
• 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
• 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 instead tied to your cybernetics
• vehicle combat is added to the game, you can even use your katana on your bike
• vehicles are no longer bought from fixers, but bought through a website set up by mama welles
• 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
I haven't been paying super close attention to the DLC or its story so I can play it fresh, but I can reccomend the base game. I really enjoyed it on its own, very good story that was very well written and voice acted. It lacks the sandbox polish that something like GTA has, but has an incredible story, character ensemble, and the world building is top tier.
I'm stoked for the DLC to drop so I can get some of these features and more story!