both (people); the two of them
Refers to two people together, often used adverbially to mean 'both' or 'the two of them' in a sentence.
二人とも元気ですか。
Are both of you doing well?
二人とも同じ意見だった。
Both of them had the same opinion.
Both of them are busy, so it looks like we won't be able to meet until next week.
They both got accepted into the same university.
Both of them are doctors.