Something like this is 3+ years in the making. I found an article from Jan 2020 showing trigger was on board before the game even launched. Before they can announce partnerships like this things have to be approved in the pipeline for a while or you risk bad press if it falls through.

https://www.theverge.com/2020/6/25/21303233/cyberpunk-2077-anime-edgerunners-netflix-studio-trigger-2022-release-date

Edit: Heck even Arcane was pitched between 2014-2015. It took 8 years to come out, but it wasn't from an already existing anime studio so developing strategies for how to make it probably took some major logistics to do in house.

While not often said enough the anime really helped shed a light on Night City as it impacts the world. The overall story of C2077 and V was bland but the world genuinely felt lived in as you watch people succumb to their vices everywhere you look.

Night City was beautiful, tragic, and the city itself changed the lives of everyone in the game, except for V. I think that's why it's so hard to connect with the game. Because you control all of V's choices, Night City doesn't feel like it's in control of you.