When Idris Elba was first cast in James Gunn's upcoming Suicide squad reboot/sequel mash-up, it was assumed that he was replacing Will Smith directly as the new Deadshot. That turned out not to be the case as it was revealed that he'll be playing a new character to the franchise, and we might now have an indication of who that will be.
According to Forbes, Elba will be playing Ben Turner (a.k.a Bronze Tiger), who first appeared back in 1975 and was played by Michael Jai White on Arrow briefly in season 2 and then more centrally in season 7. He has traditionally been a member of Taskforce X in the comics, is classed as one of its leaders and was one of the group's first recruits.
If this rumour is correct, Elba would be joining returning cast members Margot Robbie, Jai Courtney, and Joel Kinnaman, as well as Daniela Melchior, who is playing Ratcatcher and David Dastmalchian, who is set to play Pola-Dot Man. King Shark is also set to be part of the character roster, but he remains uncast despite rumours that long-time Gunn collaborator Michael Rooker was in the frame.
In terms of the story, we don't yet know very much. There is some belief that Benicio Del Toro is playing the main villain - The Mayor - who has been described as "irascible old warrior who lives for war." It definitely sounds like it's shaping up to be interesting.