Kudos to you, Tez for trying to give the benefit of the doubt.
The only problem with interpreting the question this way is that he said Mexican, which is a nationality, and Black, which refers to an ethnic group, some of whom are of Cuban, Mexican, United States, Canadian, English, or some other nationality.
I would venture that there are regional differences in training methods and stragegy preferences, but that would be about it.
One really cannot base it on ethnicity because for the most part, aside from skin tone, the only factor ethnicity really plays is differences in average height and build, but these are mostly discounted by weight class. A guy who is 6'3 and 200lbs. will fight differently than a 5'10 boxer who is 200lbs. This has nothing to do with ethnicity, though.
There may be certain cultural preferrences in terms of stylistic factors, but that only accounts for style. The rest really will not be based on ethnicity, but on training and personal dedication, which can vary greatly from person to person, regardless of ethnic group.
Daniel