Batman v Superman Producer Hints at Flash/Cyborg Team-Up in Flash Solo Film
"As you can imagine, when we get to the Flash movie, Ezra Miller and Ray Fisher - who plays Cyborg - are kind of our youngest characters, and they have a really nice comradery with each other. Ezra is super funny, so the tone of that film will be very different than the rest of them."
Producer Deborah Snyder said this in a conversation with Forbes. all but revealing that Cyborg will be joining the Flash in his solo film. The comments also coincide with Snyder's recent comments that there will be strong tonal shifts within the universe, which makes sense given the drastically differing heroes set to come together.
The Flash gets his own film March 16, 2018, five months after Justice League Part One. Cyborg has a film dated for April 3, 2020, though there's no guarantee really until the studio learns of how well Cyborg as a character is received. Which would make sense then to have him appear outside of Justice League. To test the waters, so to speak.
Source: Slashfilm