person of color vs someone

person of color and someone both are nouns.

Word	Noun	Adjective	Verb	Adverb
person of color	Yes	No	No	No
someone	Yes	No	No	No

As nouns, someone is a hypernym of person of color; that is, someone is a word with a broader meaning than person of color:

person of color: (formal) any non-European non-white person
someone: a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential

Other hypernyms of person of color include individual, mortal, person, somebody, soul.

person of color (noun)	someone (noun)
(formal) any non-European non-white person	a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential