By 'Africa', I'm going to assume you mean 'sub-Saharan Africa', which is what most people think of when they think 'Africa'. Egypt, Carthage, Byzantine Rome, and Moorish North Africa tend to show up as different influences on a setting and are often loosely bundled with or are the boundary of the normal European inspired portions of a typical game world because those cultures interacted with the European during antiquity and the middle ages.
I haven't, though I have some interest in it purely out of curiosity. There are a couple of times I've been really tempted to pick up a copy of the 3e Nyambe source book, but I never can find a real justification to do it. As is true with most homebrew worlds, various parts of the worlds are fantasy pastiches of romanticized real world cultures and there is a portion of my world that is loosely 'Africa' with dark skinned peoples and immortal demigod kings ruling elephant riding armies from leopard skin covered thrones.
I've never felt the need to set a campaign or adventure there though, so its only a sketch in my head and rarely interacts with my actual games. Occasionally I'll have wealthy merchants from that part of the world in cloth of gold and silk trading exotic items to establish the cosmopolitan nature of a great metropolis, but for the most part it remains just the unglimpsed distant exotic south.
There are several issues with gaming in the setting.
1) I have no deep knowledge of African culture, and no real interest in exploring it for its own sake.
2) I can think of nothing which for me the African culture is particularly necessary to explore a subject or theme in a compelling way. This is possibly a result of ignorance, but even if I could cure my own ignorance any myth building here has the problem of anything that requires a large amount of exposition to become clear and understandable to a player. The more unique the setting, the longer time the player must be in the campaign to really get the tropes and be able to play their character 'correctly'.
3) Unlike say the Celtic, Egypt, Norse, Greek, or Hindu cultures, the African cultures didn't produce an easily accessible body of heroic myth literature that can be used to draw inspiration. Rather, most of it is either Animistic or Animism in an transition to polytheism, probably equivalent to pre-Homeric Greek myth with equivalent disorganization and is really hard to use or find works in English on, even if you went to a good college library. Worse, you don't get a lot of resonance in the average American group as even the African Americans aren't actually part of African culture. I have first hand experience with Carribean culture, and that's a step closer, but any influence that might have on my stories (Anansi tales, for example) tends to get indistinguishable from Aesop, Brother's Grimm, or Jungle Book influences. To the extent that I want to bring Animistic pre-polytheistic influences into my world, North American culture and myth is just a lot more accessible in terms of what you can find in a library and in terms of resonance with the average American player.
4) Because of real world history, you have to be really careful about introducing any African inspired themes without offending people. You have to either romanticize the heck out of it, which become boring and dishonest eventually, because really that's avoiding the interesting problems the reality of human existence raises, or else you have to have players that also know that any Norse or Scottish pastiche would be filled with murder, stealing from your neighbors, and cattle rustling as an accepted profession as well and you aren't specifically picking on anyone or any group in portraying the general ugliness of humanity. What makes this particularly hard is that each culture tends to accept and romanticize its own savagery - for a Northern European this is the Conan material or as another good example Pirates - while responding all alien savagery as being ignorant, bestial and evil. And that's pretty universal as far as I know, so that I'm pretty sure in Africa its at least somewhat the other way around (our brutality is justified, but those Europeans are soulless demonic brutes). As such, I feel any attempt to include Africa in any way would be pigeon holed in the mind of everyone else into a modern political discussion or some modern racial stereotype or reaction to some modern racial stereotype even if my actual inspiration was say Roman racial stereotypes or actual African culture circa the 16th century. This is going to be at best a distraction, and at worse breed all sorts of arguments. So, in general I end up forced to something close to a movie director that dares not cast a black actor in a role because its all downside and no upside since it will inevitably be seen not as 'this actor is good for the part' but a comment on race (positive or negative) based on the depiction of the character. You don't really dare show an black skinned NPC in European platemail, or half naked, scarified, and wearing cotton bands as padded armor because either is seen as a statement and someone would see it as a negative statement. The result is sadly 99% 'this racial appearance is not appearing in my campaign'. And if you were actually going to publish an adventure, that risk would be an order of magnitude greater. Heck, and even discussing this is probably offending someone, so there was a cautionary part of me saying from the beginning, "Don't respond or else lie and say how cool and how positive you see the whole thing and how unreasonable it is that Africa is largely ignored in gaming."
But, if I was a brand manager I'd look at a proposal to do anything with sub-Saharan African tropes as potential dynamite to be carefully diffused and round filed, just because there is no amount of potential sales that offsets the risk someone decides you haven't been 'sensitive' enough and launches a crusade. On a small scale this is also why I don't have tons of interest, even though I'd describe my campaign world as a sort of Hindu-European fusion (imagine Europe with real magic, and Hinduism replacing the Catholic church) and try mitigate a tendency to pastiches by blending them together in various ways (Indonesia-Ireland, India-Italy, China-Rome, France-Japan, Persian-Elizabethan England, Norse Mongols).
In short, don't be surprised if no matter how cool your Africa product is (Nyambe, for example) it gets a relatively cool reception.
There are Kalamar, Pathfinder and now 5E D&D pictures of dark-skinned people, often in non-African styled clothes. Kodo is a chance to play those without having to be from 'that distant land'. I guess that is the main problem getting them involved, if people always place the 'Africa-styled continent distant from where all the main action is.
