It's another one of those "It's complicated" things.
In general, you can assume it is Muslim vs Christian vs old religion (sort of a mix of animism, protective spirits and ancestor worship. You got to be born into it to have the vaguest clue, and I am not sure it applies even then.) So far, so complex.
Then you have the tribal aspects. Most tribes are not monolithic - they'll contain a mix of the various religions, and you can move tribes with relative ease by marriage, physical movement (if you are wealthy enough) or economic status. A lot of the so called "tribes" in central Afrique are more economic than separate blood lines (Hutu and Tutsi in Rwanda were a prime example - thanks Belgium). It gets messy fast.
Say you are in the top tier of the top tribe. Who is trying to pull you down? Another tribal faction of a different religion? One of your own tribal factions? A different tribe of the same religion? Alliances shift with every marriage. It gets confusing, so the rule of thumb is to kill your enemies and watch your friends VERY closely.