Both are referred to as "black" (or worse), anywhere they go in the world, and both suffer the effects, prejudice and discrimination of racism - anywhere they go in the world.
Another fan fact - your hypothetical Jamaican and Nigerian, are the most likely to type "How does country X treat black people" before deciding whether to visit a country on holiday - something very few other people (if any) do - so there is a lot that binds the Jamaican and Nigerian together - the nonsensical (but very problematic) notion of "race".
Both are referred to as "black" (or worse), anywhere they go in the world, and both suffer the effects, prejudice and discrimination of racism - anywhere they go in the world.
Another fan fact - your hypothetical Jamaican and Nigerian, are the most likely to type "How does country X treat black people" before deciding whether to visit a country on holiday - something very few other people (if any) do - so there is a lot that binds the Jamaican and Nigerian together - the nonsensical (but very problematic) notion of "race".
HTH