Producer Deborah Snyder all but confirmed Cyborg for The Flash a while back. Likewise, The Flash director Rick Famuyiwa seemingly confirmed an appearance by Ray Fisher as Cyborg alongside Ezra Miller as The Flash as well.
Rick Famuyiwa posted an image of a new revised script for The Flash with what looks to be a Funko Pop figure of The Flash along with a Cyborg Funko Pop figure.
Check out The Flash script image where we see it features revisions by Famuyiwa:
Here is the Cyborg Funko where it seems as if the feet match (via reddit):
I believe it’s been said or rumored that WB is building up to the 2020 Cyborg movie by including Cyborg in The Flash movie (and obviously the Justice League films). I also wouldn’t be surprised if each Justice League standalone movie features other members as well.
The Flash movie has a March 16, 2018 also starring Billy Crudup as Henry Allen, Kiersey Clemons as Iris West, with Phil Lord and Chris Miller contributing to the story/script as well.