represent (someone's) interests

Translations
представлять интересы (кого-то)
The union is there to represent the workers' interests.
Профсоюз существует, чтобы представлять интересы рабочих.
Definitions
To act on behalf of someone to advocate for or promote their needs, desires, or concerns, often in a professional or legal context.
Words
interest

noun
интерес
represent

verb
представлять