In terms of church fathers all of the following were native Afrikans: Basilides, Valentinus, Tertullian, Origen, Cyprian, Athanasius, Arius, and Augustine, and there were others but these are the most prominent.
But having a Black pope is like having a Black president (of the U.S.). Despite their racial background they are symbols and agents of the institutions they represent, and these institutions represent white power. Having a Black pope won't address the historical genocides and misdeeds of the church. Having a Black pope won't stop the church from imposing European cultural assumptions and values upon other people. And having a Black pope won't address the Hellenized image of the Christ, which has no basis in history. This institution (the Roman Catholic church), like the U.S. presidency, is a member of “Club White Supremacy.” The doctrines, histories, and bureaucracies of these institutions will dictate the overall direction the offices' occupant takes, despite his or her ethnicity or racial background—and the institution will either accepted or rejected their individual program—always making sure that at least the status quo is maintained, and at best the goals of the institution are expanded.