Since the 17th century American governments have been hiring Native Americans as military auxiliaries, usually as scouts and trackers. The job paid well and the many tribes were often fighting one another or waiting to because of ancient feuds. So it was easy to hire the more expert tribesmen to do what they were eager to do (find and kill their enemies). The use of the “Indian Scouts” grew after the American Revolution was over and peaked in the late 19th century. There was a major revival during World War II as thousands of Alaskans Eskimos were recruited to patrol the vast arctic borders. Early in the war the Japanese did invade a few of the Aleutian Islands but were soon driven out.
All Indian Scouts were officially disbanded in 1947 but the Alaskan Scouts (now part of the 201st Infantry Group) continued to serve during the Cold War, to keep Soviet agents out. That apparently worked because after the Cold War ended Soviet era records revealed that the only Russians who got into Alaska (often with an assist from Alaskan Scouts) were Russians fleeing to the United States.
Since (and before) World War II American troops overseas have continued to hire knowledgeable locals as scouts and interpreters. Perhaps the most famous and enduring of these were the Philippines Scouts, who were organized before World War II as the core of the army for the soon-to-be independent Philippines. That independence was delayed a year by Japanese invasion and occupation. After the invasion many of the scouts refused to surrender and headed for the mountains and were a major part of the anti-Japanese resistance. After the war the “Scout Rangers” became the elite infantry of the Filipino Army.
Meanwhile one American tribe, the Tohono O'odham of Arizona (and northern Mexico), still provides a small units of scouts and trackers for U.S. Immigration and Customs Enforcement (ICE) and works along a 122 kilometers stretch of the Mexican border. These scouts are called the Shadow Wolves and are sometimes called to assist along other parts of the border. The Shadow Wolves usually has only 12-20 scouts (or Patrol Officers) and currently employ expert trackers from other tribes (Navajo, Kiowa, Sioux, Blackfeet, Yurok, Omaha, Yaqui and Pima). The Tohono O'odham were long neighbors of the Apache. Often enemies, the two tribes were sometimes allies against Mexicans and Americans moving into their territory.