The English idiom, To be on a roll, means to enjoy continuing success. In this phrase, a roll means “the process of rolling,” like a wheel—not a bread-roll! So, being on a roll literally means moving forward. We can also say you’re really rolling now, let’s roll!, and even let’s get this ball rolling. In all cases, to roll means to make progress. But on a roll implies more than one success in a row:
He just won three bets in a row; he’s on a roll.
After several hit movies in a row, Marvel studios is on a roll.