Ryan Coogler
The Oscar nominee said the "situation should never have happened", but insisted he has "moved on" from the incident.
Only a “tight-knit” circle of friends and his team were aware of the actor’s diagnosis.
"Because he was a caretaker, a leader and a man of faith, dignity and pride, he shielded his collaborators from his suffering," the filmmaker wrote.
This year’s shortlist included Trump, Putin, and families separated at the US border.