The case of the Little Shell Tribe of Chippewa Cree of Montana does stand out as unique. All seven of the federally acknowledged tribes in Montana wanted the Little Shell to be federally acknowledged, and as far as I know, they still do.
The Little Shell were big time buffalo hunters. Their language, Michif, is virtually perfect Cree as to the verb, but the nouns are French. Except for a Cree family line or two, their descent is altogether Chippewa.
In the Federal Register, the Little Shell got a proposed finding to acknowledge which was reversed in the final determination. But, the text of the final determination not to federally recognize the Tribe, listed several pathways by which Congress could recognize the Tribe, should Congress desire to do so.