Cyberpunk 2077 will let you be more aggro than Geralt of Rivia with some restrictions, both for in-fiction reasons and practical game concerns. If you're the kind of person who likes picking fights with NPCs for no good reason, developer CD Projekt Red has confirmed that you'll be mostly free to start shit as you please in Night City.
Reddit user masoncool4566 posed the initial question on "how we can interact with the city in volent ways" and if you can straight up "kill regular people" to the Cyberpunk 2077 Twitter account. Yes, they did realize later on that the question made them "sound like a psycho." Uncomfortable context aside, the account's answer gave us a better understanding of how Cyberpunk 2077 will approach a common concern of open-world games.
"Hey there - you won't be able to attack children or NPCs connected with the plot, but other than that you can be aggressive towards most people you meet," the Cyberpunk 2077 Twitter account responded. Then it ended the message with a winky face, which I'll assume was an attempt to defuse the tension of a stranger coming up to you and asking if you'll let them murder virtual people.
That puts Cyberpunk 2077 in roughly the same camp as Skyrim, which lets you kill most NPCs but still protects some plot-essential ones (and children). It's a change in direction for CD Projekt Red, since The Witcher 3 didn't let you attack everyday citizens in any context, barring exploits. Such things would be out of character for Geralt the consummate professional, but CDPR means to let you shape Cyberpunk protagonist V on a more fundamental level.
The studio confirmed its Twitter answer in a followup response to PC Gamer, also adding that starting fights could get your character in trouble; police will come down on you if you trouble their corporate overlords, while local gangs won't take kindly to you causing problems on their turf either.