Why is Mayweather fighting Pacquiao again? Who is favourite? And is it a one-off?

On Monday, Floyd Mayweather and Manny Pacquiao stunned the boxing world by announcing a professional rematch - 11 years after their first bout.

source https://www.skysports.com/boxing/news/12040/13511616/floyd-mayweather-vs-manny-pacquiao-who-is-favourite-and-why-is-fight-happening-in-2026-in-las-vegas