The main themes include racism, of course. The Green Book itself was a product of the segregated society. Then there's the theme of personal growth. The white driver grows as a person by learning about the real experiences of the black pianist. And there's also the theme of hope. Despite the difficult circumstances, the pianist continues to perform and the two men continue their journey together, showing that there's hope even in a racially divided world.
One of the main themes is the struggle against racial inequality. The story in the Green Book is full of instances where the black pianist has to face discrimination, from not being able to use certain facilities to being treated with disrespect. Friendship is another strong theme. The relationship between the pianist and his driver develops in an interesting way, starting from a business - like arrangement to a real friendship. Additionally, the theme of cultural exploration is there. The driver gets to know more about the African - American culture through his time with the pianist.
Racial discrimination is a major theme. It shows how African - Americans were treated differently in the South. Also, friendship is a key theme as the two main characters from different races form a bond. Another theme is the power of art, as the pianist uses his music to bridge some gaps.