Manga is generally in black and white. It's a traditional style that focuses more on the linework and storytelling. However, there are a few exceptions where color is used for special purposes or in specific publications.
The majority of manga are not in color. It's a common practice in the manga industry to use black and white for regular publications. But for certain limited series or special projects, color might be employed to make them stand out.
The JoJo manga is mainly presented in black and white. However, there might be some special editions or colored illustrations for promotional purposes, but the standard version is not in color.