According to a statement from the channel on Twitter, cheese sauce is not available everywhere and "its inclusion [on the menu] According to a Chewboom report, customers can currently get it at 436 US locations, although others will likely offer it once demand grows.
The only drawback is that unlike FCA's existing range of dip sauces, the new cheese sauce is not free. A three ounce portion will cost you $ 1.19. Considering the immense regret that you feel do not when trying, it seems like a pretty reasonable price.
h / t Chewboom