wp query – How can I create a custom taxonomy relationship?

I create two custom taxonomies:

  • category (Cars, pets, etc.).
  • region (New York, Washington, etc.).

Now I have to make archives {Category} in the {Region} (for example cars in the new York) and get snails for it (mysite.com/ads/cars/nyc or mysite.com/ads/cars/?city=New+York).
How can I stop such a dependency?

I had only one idea – the use of subcategories (eg Cars is parent, New York is kid), but I think it's not a good solution.

WooCommerce has a nice solution with its filters (attributes), but I do not know how it works.