Hunter-gatherers are the very definition of subsistance farmers and i doubt any of them produce anything on their own they arent immediately eating.
HOWEVER. Trade. Start trading there and the hunter gatherers of africa will be more than happy to provide slaves (other tribes) and ivory in return for guns and ammunition. (perfect place to dump 20yo tech)
Or for that matter using guns as a currency to buy tribes. Provide guns for 2 armies, get one army and a ally of sorts vs local foes who will no doubt love to annex all those locals you fought. Or atleast take what they are allowed. And with ongoing trade and development such a friend, well, vassal would eventually be integrated. Especially with accepting the one true faith.