The central biochip in Cyberpunk 2077 is called the Relic.
The Relic is an experimental Arasaka biochip designed to store and reproduce a human personality construct. During the Konpeki Plaza heist, V and Jackie Welles obtain it as part of Dexter DeShawn’s plan. After the heist goes wrong, the damaged chip is inserted into V’s neural interface, beginning the main conflict of the game.
Johnny Silverhand’s digital personality is stored on the Relic, so the device links the game’s corporate conspiracy with V’s personal survival crisis. The Relic is not the same thing as Soulkiller, the technology used to create digital personality constructs, and it is not the Blackwall, the barrier separating protected networks from rogue artificial intelligences.