Thank you for your question.
In short, waxing immediately prior to laser hair removal will likely decrease the effectiveness of the laser providing short term, rather than long term, reduction in hair.
More specifically, lasers target the pigment of hairs at the base of the follicle (in the growth phase), which allows the follicle to be destroyed and inhibits new hair growth. Waxing removes hair from the follicle (including hairs at the base)
Without the hair, and thus pigment, at the base of the follicle the laser does not have it target and is therefore not as effective at destroying the follicle and decreasing future hair growth.
I hope this helps.