African slaves brought to the United States, and their descendants, have had a history of cultural exchange, and notably intermarriage, with the Native peoples they encountered and their descendants (largely in the American South). This cultural mixing is also believed to be the reason why certain phenotypes (physical characteristics) common within Native peoples also occur in the African American population.
Native American groups have had both positive and strained relationships with the Africans and African Americans they encountered. Some groups were more accepting of Africans than others and welcomed them as full members of their respective cultures and communities. Some Native Americans, especially as they became more assimilated into the dominant American culture (aided in large part by White intermarriage with Natives), came to treat African Americans with contempt, as did much of the White population. There were disagreements among Native peoples concerning the role of African people in their communities; some tribal factions (notably the Keetoowah Society of the Cherokee) were opposed to slavery [1] while others were in support of it; this was part of a wider split among Native people who were either for or against assimilation into the increasingly dominant White American culture of the early-to-mid 19th century.
Some African Americans participated in warfare against Native Americans, especially in the Western frontier states as members of military units such as the Buffalo Soldiers. On the other hand, many Native Americans and African-descended people fought alongside one another in armed struggles of resistance against U.S. expansion into Native territories, as well as resistance against slavery and racism.
There are efforts currently underway to promote greater cooperation and understanding among both modern African American and Native American tribal groups. Some intermarriage still occurs between these groups; some African Americans who descend from or who identify as Black Indians identify strongly with the Native cultural traditions that they were raised with.