Do you need the base game for Cyberpunk 2077: Phantom Liberty?
Yes. Cyberpunk 2077: Phantom Liberty is extra content and only works if Cyberpunk 2077 is already on the same account and the same platform. Without the base game you can redeem the code but play nothing.
Same account, same platform
Buy the DLC for the platform where you already own Cyberpunk 2077. Redeeming it on another account or console makes the content unusable, and that cannot be reversed.