Who is Tupac Shakur from After Tupac and D Foster and what is their importance?

Tupac Shakur is the real-life rap artist who was gunned down in 1996. The main characters admire Tupac and feel that he addresses issues that are important to them. An initial shooting (which Tupac survived), a criminal case and eventual incarceration, and then a second, fatal shooting, are all referenced in the novel.