Federally recognized tribes are subject to numerous federal laws that deal specifically with them about taxation.
Federally recognized tribes are sovereign legal entities, similar to state governments. They have all the rights and attributes of a sovereign entity such as a state. They have a constitutionally guaranteed status as sovereign entities. They are not subject to tax based on this. Federally recognized tribal governments are a unique set of entities in the United States in this respect.
Revenue Ruling 67-284 states that an Indian tribe, as an income producing entity, is not subject to income taxation. However, income earned, if not otherwise exempt from income taxation, would be included in the gross income of the Indian tribal member when distributed or constructively received by the tribal member. Examples of income that aren’t taxable to Indian tribal members include payments made under certain general welfare programs and payments exempt under the Per Capita Act.