Avery and his nephew, Brendan Dassey, are both serving life sentences for Halbach's murder.
Dateline promises "fresh, new interviews and rare footage of a sit-down conducted in 2005 with Penny Beerntsen, the victim of the sexual assault case for which Avery was wrongfully convicted and spent 15 years in jail.
Canning tells TODAY's TMJ4 that she also interviewed prosecutor Ken Kratz, who had a "surprising admission."
"We'll tell you what the next step in the case is, which is very important, where does it go from here? There's so much noise, there's so much outcry, but what happens next? Is it realistic that Steven Avery gets a new trial or that Brendan Dassey could?" Canning said.
Canning says the special will also cover the portion of the documentary where Avery's lawyers discovered a vial of his blood that appeared to be tampered with.
"In reality, it may not be so black and white, so we brought in a blood expert who breaks down what you should be seeing, what you shouldn't be seeing, so for me that was kind of an eye-opening moment as a viewer of the documentary," Canning said.