According to ESPN's Jeremy Fowler, the Bills "were trying to get involved last year" in a trade for Martavis Bryant.
“We assume this happened around the trade deadline when Bryant voiced his desire to leave Pittsburgh when he lost his starting job to JuJu Smith-Schuster. Fowler believes teams came to the Steelers offering a fourth-rounder, but it wasn't enough in Pittsburgh's eyes. Fowler, however, does think a second- or high third-rounder could get the deal done this offseason. Bryant's contract expires after 2018, and he isn't expected to accept a long-term deal with the Steelers due to his desire to be a No. 1 receiver. That obviously isn't happening with the Steelers.”
-espn.com