Which of these is NOT a playable character in the 2016 video game Overwatch?

Invoker is not a playable character in the 2016 video game Overwatch. Invoker is a hero from a different video game called Dota 2, developed by Valve Corporation. Overwatch, developed by Blizzard Entertainment, features a roster of unique heroes, each with its own abilities and playstyle. However, Invoker is not part of the Overwatch universe. The confusion may arise from the fact that different video games have distinct sets of characters, and Invoker is specifically associated with the Dota 2 game. In Overwatch, you won't find a hero named Invoker among the playable characters.