Specifically refers to one's daughter's husband. More precise than 義理の息子, which can also mean a stepson.
My son-in-law will be transferred overseas next month.
娘婿と一緒に庭の手入れをした。
I did some gardening with my son-in-law.
He became the company president's son-in-law.
They decided to take in a son-in-law as their heir.