Apple iPhone could possibly be used to unlock your car without using actual keys. A patent granted to Apple (Source: USPTO) in US mentions about accessing a vehicle using portable devices. The abstract in the patent mentions the following:
“A primary portable device can access a vehicle by transmitting an activation message including a vehicle access credential to the vehicle. The primary portable device can additionally enable a secondary portable device to access the vehicle by transmitting the vehicle access credential to the secondary portable device. The connection between the primary portable device, secondary portable device, and vehicle can be based on a short-range wireless protocol, such as Bluetooth or Bluetooth LE.”
This hints towards Apple iPhone and another Apple device most likely Apple Watch to be used for replacing your car keys.