You cannot apply both to the same layer. You have two options:
- (best option for an efficient workflow in an effects heavy project) Warp Stabilize, render a DI (digital intermediate) then replace the original footage with the stabilized footage
- (or - larger file by far for the aep and potential problems abound) Warp stabilize, pre-compose, then camera track the pre comp.
Unless the shot is very short and you don't plan to do a bunch of other things to the shot I would go with the first option.