A polite expression asking someone to treat you well or to cooperate — equivalent to 'please treat me well' or 'I look forward to working with you.' Used when requesting someone's goodwill or cooperation.
新しいプロジェクトの担当になりました。今後ともよろしくお付き合いください。
I've been assigned to the new project. I look forward to working with you.
来月から部署が変わります。これからもぜひよろしくお付き合いください。
My department is changing next month. I hope we can continue to work well together.
イベントに参加してくださる皆様、どうぞよろしくお付き合いください。
To everyone participating in the event, please kindly cooperate/participate (we appreciate your cooperation).