older sister and her husband
Refers to one's own older sister and her husband as a couple. Used when talking about them together.
My older sister and her husband are planning to move to a new house next month.
I received a souvenir from my older sister and her husband.
Refers to one's younger sister and her husband, while 姉夫婦 is specifically for an older sister.
Compound of 姉 (ane, 'older sister') and 夫婦 (fūfu, 'married couple').