Ta-Nehesi Coates is a New York Times bestselling author who wrote “Between the World and Me” and the Black Panther comic series. I thought it was very interesting how he agreed to write the comic books because he did not have a background in comic book writing. However, I completely agree that he was the perfect choice because he would give the comic series an extra dimension from his literary background in African American studies.
I think that the comics itself cannot be classified as fanfiction because it is endorsed by Marvel and it is available for sale on his website. I believe he is essentially continuing the franchise after its movie and helping it prosper. I also do not think it should be considered fanfiction because it does not significantly alter the setting of the original comic book character and keeps most, if not all, the elements the same.