Sancho has long been a Man United transfer target, with the Red Devils an admirer of the England international.
The 21-year-old was heavily linked with a move to United last summer, but the Premier League side could not meet Dortmund's asking price for their prized asset.
However, he could be on the move to Old Trafford this summer as Daily Star report United have made signing Sancho their top transfer priority.
However, Sancho will not come on the cheap but United believe the English winger will be available for a figure close to £80m, which is a significant drop from what Dortmund were asking for the player last summer.
The English outlet add United would also love to sign Sancho's Dortmund teammate, Erling Haaland, but the Norwegian, who has attracted interest from several top European clubs, is not the club's priority.
They also claim United are 'increasingly optimistic' Edinson Cavani, who has been impressive of late, will agree to a new one-year deal, which would extend his stay at the club beyond the end of the season.