African philosophy is considered to be a relatively new discipline, as it took off around 1970’s. It was the time when African scholars started the search for the national philosophy to build the identity of African states and their citizens.
To dive further to the issue, you can go on and check out a book of Munyaradzi Mawere and Tapuwa R. Mubaya, named African Philosophy and Thought Systems: A Search for a Culture and Philosophy of Belonging. IT appears to be well-written thorough research of African philosophy and debates around it. From the reviews we know, that the book is written in an accessible language and makes a decent paedagogical text. Also, it might provide you with several interesting perspectives and insights.
Also, StudentShare database is full of papers on the issue. Try downloading several of them.