CD Projekt Red is either extremely unlucky, or has someone working against them from the inside. A couple of years ago The Witcher 3's script and quest details got released in a massive leak, and now we have the same thing happening with Cyberpunk 2077, though with the added twist that CDPR is also being blackmailed by whoever stole the data.
For obvious reasons CDPR is not going to accept the demand for ransom, so be prepared for an eventual leak as it could contain massive story spoilers. Mind you, all of this is from an early version of Cyberpunk 2077 and as such is "largely unrepresentative of the current vision for the game", but even still its best to avoid reading the leaks as it could potentially ruin your playthrough.
There is unfortunately no more information to share about this whole event, but I must admit I'm impressed CDPR even went public with the whole thing instead of just denying the leaks as mere rumors. On a somewhat mean-spirited and ironic note I do also find it funny that Cyberpunk 2077 - a game about corporate espionage, hacking, and plenty of backroom deals - has suffered from exactly the type of thing its supposed to portray.
And finally, here's the full post from CDPR, just in case I missed any details you might be interested in: