immune vs unaffected

immune is a noun but unaffected is not a noun.

Word	Noun	Adjective	Verb	Adverb
immune	Yes	Yes	No	No
unaffected	No	Yes	No	No

immune (noun)	unaffected (noun)
a person who is immune to a particular infection

immune (adjective)	unaffected (adjective)
relating to the condition of immunity	undergoing no change when acted upon
secure against	free of artificiality; sincere and genuine
(usually followed by `to') not affected by a given influence	emotionally unmoved
relating to or conferring immunity (to disease or infection)	unaware of or indifferent to