Higher springs for the front struts and rear torsion beam suspension. It's also possible spring spacers would work if you can find the right diameter for the Trailblazer springs. You also have to make sure there is enough adjustment in the alignment settings to compensate for the lift and check the extended length of the front struts and rear shocks so they don't top out. Unfortunately nobody makes anything like this yet, so you'd have to do some research to see if anything is compatible.
One word of caution, modifying anything on the suspension like this will void any suspension and steering related parts under the factory warranty.