In the US, when writing about race issues, the common terms are (now most common) "African-Americans," or (now less common) "blacks," or sometimes (though now more rarely) "Afro-Americans," and "whites." Please note: no article (e.g., "the blacks" or "the whites") is used for any of these.
An audience outside of the US may have other preferred usages. For further background, you may want to take a look through some of these links:
race whites blacks - Google Search
Afro-American - Google Search
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