someone vs being

someone and being both are nouns.

Word	Noun	Adjective	Verb	Adverb
someone	Yes	No	No	No
being	Yes	No	No	No

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

someone: a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential
being: a living thing that has (or can develop) the ability to act or function independently

Other hypernyms of someone include organism.

someone (noun)	being (noun)
a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential	a living thing that has (or can develop) the ability to act or function independently
	the state or fact of existing