in the flesh vs in-person

in the flesh and in-person both are adjectives.

Word	Noun	Adjective	Verb	Adverb
in the flesh	No	Yes	No	No
in-person	No	Yes	No	No

As adjectives, in the flesh and in-person are synonyms defined as:

in the flesh and in-person: an appearance carried out personally in someone else's physical presence

in the flesh (adjective)	in-person (adjective)
an appearance carried out personally in someone else's physical presence	an appearance carried out personally in someone else's physical presence