North American Mastiff.
https://thedogsjournal.com/north-american-mastiff-dog-breed/
The North American Mastiff was first developed in the 1980s by Fredericka Wagner; one of the owners of the Fly Wing Farms in Ohio. Fredricka had been a dog breeder, constantly trying different combinations. One day, she planned to crossbreed the Kangal Shepherd with the English Mastiff, and the North American Mastiff was born.