They get an established left tackle, who was considered a top ten player at his position, prior to some injuries in 2017. Glenn will be 29-years-old in September. The Bengals keep a first round pick – they move back nine spots in the draft.
The Bills get the No. 12 pick and the Bengals' sixth round pick (pick 190) in the 2018 NFL Draft. The Bengals get Glenn, the No. 21 pick and the Bills' fifth round pick (pick 158) in April's draft.
I wrote about Glenn at length before the NFL trade deadline. This trade fills a need for the Bengals and they still have 11 draft picks.