Apple's doorbell will connect to smart locks from other manufacturers installed in the home. The main condition is that they work according to Apple's HomeKit protocol.
The idea is very simple: integrate Face ID technology into the door and open the door not with boring keys, cards, codes or fingerprints, but with facial recognition technology. According to Bloomberg's Mark Gurman, the doorbell will work via a wireless protocol. According to him, the bell will have an Apple-developed Proxima chip, as well as the company's own Wi-Fi and Bluetooth modules.
All this information coincides with rumors that Apple is developing a hub for smart home management and its own security cameras. This doorbell should not be expected soon - it is expected to be released on the market in at least a year.