While promoting “Outside the Wire” with co-star Damson Idris, Mackie opened up to Extra’s Nate Burleson about his late friend Chadwick Boseman. Mackie explained:
I met Chad in ‘98, ’99, so I've known him, I knew him for a long time… What was great about Chad… unlike everybody else today, Chad kept his circle close to his vest. He kept his world very private… That's one thing, one of the things, that we had in common.
Our time at work was our time at work, but our time at home was our time at home, and we didn't allow the two to cross because that's what keeps you grounded. That's what you know if you look at the relationship he had with his wife, you look at the relationship he had with his family. You know, Chad and I we were country boys… You come home and, you know, your mama make them collard greens and cornbread, ya know? She make them smothered turkey wings, some potato salad. That's home.
Mackie then talked about why he can't bring himself to see Chadwick in Netflix's Ma Rainey's Black Bottom saying:
Ma Rainey's Black Bottom holds a very special place [Mackie starred as Ma’s nephew in the 2003 Broadway revival of the show]. With the relationship to that, and the relationship to August Wilson, and my relationship to Chad, I haven't been able to pull myself to the point emotionally to be able to sit and take that experience in. Because I wouldn't be able to watch it for the performance and the art, it would just be too emotional of a process for me.