Please I want to know if CO2 laser treatment is actually removing tribal marks? (Photo)

The CO2 will touch on the surface of the marks, but you may want to consider some type of microneedling treatment such as the Infini. The infini uses 49 insulated needles to penetrate the skin with radio frequency at different depths. This will help stimulate collagen beneath the surface of the skin. 

A series of combination subscision tissue release and a fractionated CO2 laser will likely improve these scars to a certain degree (probably 3-6 sessions), but if you are still unhappy with the end results surgical revision might be the best answer.  Best wishes, Shobhan.