https://www.cdc.gov/importation/bringing-an-animal-into-the-united-states/dogs.html
CDC issues regulations to control the entry of dogs into the United States from other countries. These rules apply to all dogs, including puppies, service animals, and dogs that left the United States and are returning. They also apply whether you are a U.S. citizen, legal U.S. resident, or foreign national.
If you don’t follow CDC’s rules, your dog won’t be allowed to enter the United States. If denied entry, your dog will be sent back to the last country of departure at your expense.