Vehicle seat assembly and vehicle

The invention relates to a vehicle seat assembly and a vehicle including the same. The vehicle seat assembly comprises a bottom plate (500) and a cushion (100), wherein the cushion (100) is fixed to the bottom plate (500); the seat cushion (100) comprises: a cushion pad (120), a portion of the bottom surface of the cushion pad (120) being away from the base plate (500) to form a recess (123), the recess (123) being disposed adjacent to the front of the seat cushion (100); the concave part (123) is filled with the supporting part (110), so that the supporting part (110) is clamped between the cushion pad (120) and the bottom plate (500); the support portion (110) is made of an expandable foam material that can be switched between a soft state and a hard state. According to the vehicle seat assembly, the supporting part capable of being switched between the soft state and the hard state is arranged in the cushion, so that the vehicle seat can achieve the comfort performance and the anti-submarine performance at