I was doing some research on Mali and it's quite interesting.

To start off with Mali can be split into roughly three regions, the south, which is where the Government's power comes from and it gets enough rainfall to support agriculture, The governments power base comes from the Bambara people who live in that area.

Then there is the north, which is very arid and can't support agriculture, it's populated by Berber(Tuareg) Nomads, There are numerous confederations of Tuaregs but the most powerful is the Kel Adagh. These confederations are made of 'Noble tribes' and 'peasant tribes' but within the noble tribes there is also a heirachy. In the Kel Adagh it is the Kel Afella who are the top dogs, all Kel Adagh leaders come from this group.

The FLA operate in the north and are dominated by the Kel Adagh and the Kel Afella and are the conservatives of the North, they want to preserve the status quo.
The JNIM is a Jihadist group that operate in the north as well as the centre. The Centre of Mali is a transition zone between the agricultural subsaharan south and the the dry Tuareg North. It's dominated by the Songhai people but they don't seem to have much political power in Mali.
The JNIM are led by another member of the Kel Adagh but from a lesser noble tribe, therefore he can't actually take over the Kel Adagh as he is not from the Kel Afella. This is why he is the head of JNIM instead. JNIM are sort of the anti-status Quo force in the north, they want to abolish or re arrange the power structure there, so they are not really an ally of the FLA.

Anyway, the Malians do no like the North operating outside their control and want to subjected it, the French came in and rescued the government from a Jihadi offensive but the French where there for just that, they were not interested in subjugating the North for the Malians, they were just there to fight Jihadists.
The Malians did not like this so they removed the French and replaced them with the Russians to take Kidal(the capital of Kidal province which is where the Kel Adagh powerbase is).
This stirred up the Kel Adagh who would re organise and also the Malians and Russians were not able to finish the job and suffered a severe set back which led to a reversal.

Last year both the Kel Adagh and JNIM inflicted even further loses on them and now this year they have launched a joint offensive against the Malians, so far they have retaken Kidal and taken numerous other towns.
But as I said, they are not natural allies so who knows how this will end.