go together

to look good together:
Do you think the cream dress and the blue jacket go together?
I think red and orange go together, though lots of people think they clash.
That shirt doesn't really go together with those trousers.
Do you think these colours go together?
Grey goes together with lots of colours.
The new extension goes together with the rest of the building.

to happen or be found together:
Wisdom and maturity don't necessarily go together.
Researchers have discovered that short-sightedness and high IQs seem to go together in children.

informal
If two people are going together, they have a romantic or sexual relationship with each other.
SMART Vocabulary: 関連した語句
(Cambridge Advanced Learner's Dictionary & Thesaurus からの go together の定義 © Cambridge University Press)

アメリカ英語辞典
to regularly exist at the same time, or often be found in the same place:
Movies and popcorn just seem to go together.

If items of clothing, furniture, or food go together, they look or taste good when experienced at the same time:
His suit, shirt, and tie didn't really go together.
(Cambridge Academic Content Dictionary からの go together の定義 © Cambridge University Press)

- Cambridge Dictionary