Basically fry bread is a type of bread invented due to the forced relocation and genocide of native populations in the US. Some treaties stipulated rations, which came in the form of oil and flour. Having little else to work with, they made fry bread.

A Navajo taco is named that because it's from the Navajo Nation, one of the larger nations in the SW of what is now the United States. The fact it used to be in Mexico and still has a massive hispanic population basically makes this confluence inevitable.

Basically, imagine a warm, extra thick, sorta rough tortilla. And it tastes better than you can imagine