Does a new wheel hub assembly come with a wheel bearing already pressed in there or do you need to buy a bearing separately then press it in?

A new wheel hub assembly typically comes with the wheel bearing already pressed in, so you do not need to purchase a separate bearing. This design simplifies installation, as the assembly is ready to be mounted directly onto the vehicle. However, it's always a good idea to verify the product specifications before purchasing, as there may be exceptions for certain vehicles.