Markiplier is a YouTube star often closely tied to Five Nights at Freddy's and other horror games of that ilk. He helped the indie game rise in popularity, and many were hoping to see him in the upcoming movie.
However, as confirmed in a recent stream, Markiplier will not have a cameo in Five Nights at Freddy's. Apparently, he wanted to be in the movie, but the schedule didn't line up due to him working on his own movie, Iron Lung.
Fans are hoping that if another project comes out of the Five Nights at Freddy's movie, Markiplier could be in that instead. However, it's clear that on this occasion, the YouTube star will not be making an appearance.