Zombie in Philosophy is identical to us being in all respects expect consciousness, it is totally unconscious. The possibility of zombie implies falsity of physicalism.
Zombie argument is the most influential argument against physicalism. It says that consciousness is something more than physical. We can conceive a being in all physical and functional respects identical with us but totally unconscious. It’s because of intuition that information processing in the brain could in principle be performed without phenomenal properties. There is no need for them to be phenomenal. Hence physicalism doesn’t explain phenomenal consciousness.
Dmitry Ivanov and Vladimir Spiridonov discussed the issue within a mutual project with Postnauka “Philosophy of mind from A to Z”.