Oblo is a poorly attested, unclassified, and possibly extinct language of northern Cameroon. It is, or was, spoken in a tiny area including Gobtikéré, Ouro Bé, and Ouro Badjouma, in Pitoa, Bénoué Department. (Note: the map in Ethnologue shows it in Mayo-Rey Department, possibly an error.)
Oblo has been classified as one of the Adamawa languages, but it has not been included in recent classifications. It might be best left unclassified altogether.
^Hammarström, Harald; Forkel, Robert; Haspelmath, Martin, eds. (2017). "Oblo". Glottolog 3.0. Jena, Germany: Max Planck Institute for the Science of Human History.