
One of the main reasons that the tribes of the trail of tears: the Cherokee, Chickasaw, Choctaw, Muscogee (Creek), and Seminoles were called the “Five Civilized Tribes” by Americans was *because* they had adopted slavery and other American practices (like writing, Christianity, market economies, and centralized governments).
Groups like the Creek and the Yamasee (now extinct as a tribe) were actually very prominent slave raiders in the southeast, entirely depopulating the native communities of Florida and much of Arkansas, and selling Native slaves to Englishmen in Charleston, where they were then exported to the Caribbean. At one point South Carolina exported more slaves than it imported
And the social standing of black people varied from tribe to tribe. Some groups like the Cherokee had more rigid chattel slavery like we would usually recognize, while for the Seminole black people were more just parts of the community. The Black Seminoles largely were slaves who escaped from plantations, travelled to Florida, and then joined the Seminole tribe.
As the Seminole shifted towards more dedicated chattel slavery like the Choctaw and Cherokee, a group of Black Seminoles escaped in a dramatic trek across Texas while pursued by slave catchers and the Texas rangers. They finally managed to cross the Rio Grande and settled in Mexico, where a black Seminole community still exists today
Now, many of the black Cherokee, Creek, Choctaw, Chickasaw, and Seminoles still struggle in Oklahoma, as the tribal governments have instituted rules which exclude most black people from tribal membership (as they often weren’t included in the Dawes Rolls or lack direct tribal blood). This means these black peoples don’t have access to tribal services and assistance.