This movie was originally just going to be titled 'Shaft', and people on the internet got upset about the idea of remaking the 1970s original, which is considered to be iconic. The change in name is to make it clear that this is, in fact, a sequel. Specifically, it's a sequel to the movie from 2000 which starred Samuel L. Jackson, which was itself a sequel-of-sorts to the original. This is an extension of the tale, not a re-telling of it.
Jackson appears in the movie as the father of this latest addition to the Shaft family, who's played by Jessie Usher. Richard Roundtree is also among the cast, reprising his role as the very first Shaft, or Shaft Prime, if you will. This is, as you would expect, a gritty detective drama set in Harlem that promises to pull no punches. 'Son of Shaft' has 'summer blockbuster' written all over it, and hits cinemas in the US on June 14th.