The RAND Corporation has just published a paper titled "Mapping Chinese and Russian Military and Security Exports to Africa" by Cortney Weinbaum, Melissa Shostak, Chandler Sachs, and John V. Parachini.
China and Russia are among the top five countries that export major arms to Africa and both countries have employed private military and security contractors across Africa. Russia exports more arms than China and employs a mercenary organization, the Wagner Group, in several African countries. Chinese private military contractors are almost always unarmed and are used to secure Chinese interests.