16-time WWE World Champion John Cena has main-evented multiple WrestleManias and even when he didn't, he definitely delivered memorable matches that we talk about even today. Although Cena has squared off with the likes of Triple H, The Rock, Batista, Edge, Shawn Michaels, and many other legendary wrestlers on the Grandest Stage of Sports Entertainment, there are quite a few matches that fans would have loved to witness at WrestleMania. As we gear up for WrestleMania 37, let's take a look at 5 WrestleMania feuds for John Cena that were eventually canceled.