A Black African can marry a Christian or a Jew. It is difficult for anyone to marry a Christian Jew since there is no such person. A person is either a Christian or a Jew, not both at the same time. They are two separate religions. They have been separated for about 2000 years.

Another view:

Yes they can marry under certain circumstances. It is possible to be a Messianic Jew which is essentially a Jewish Christian. They would be Jewish and then ask Christ to come into their heart and life and be their personal savior. They would see Christ as the fulfillment of Judaism and not feel compelled to abandon their Jewish traditions. Anyway, the African would likely have to be of at least one of those faiths to marry.

Answer:

The view of normative Judaism, and most Christians, is that a person is either Christian or Jewish. One who accepts Jesus as savior is fully Christian, whether or not he/she keeps Jewish precepts.

To answer the Question: A Black African may marry a Jew or a Christian. Color and geography are irrelevant. If the Black African is not Jewish, traditional Judaism states that he/she should marry within his own faith. He could convert to Judaism for marriage purposes, but this is allowed only after the fact and only if he/she actually intends to live as a Jew.

If a Black African wishes to marry a Christian and is not a Christian himself, most Christians would expect him to become Christian before the marriage.