In 'the underdoggs true story', there could be themes like self - discovery. As the underdogs face challenges, they might discover their own strengths and capabilities that they didn't know they had before. There could also be a theme of social change. If the underdogs are from a marginalized group, their success could potentially bring about positive changes in how society views that group. And of course, the classic theme of the underdog's victory, which shows that no matter how small or weak one may seem, with determination and the right attitude, great things can be achieved.
Another theme might be the power of teamwork. If it's a story about a group of underdogs, they likely had to work together to succeed. For example, they could be a ragtag sports team that learned to rely on each other's strengths. And also, the theme of hope could be present. Even when things seemed bleak, the underdogs in the story might have held on to hope and that drove them forward.