#2 John Cena will push Angle to a decent match.

Kurt Angle is now only a shade of what he once was. We can't expect him to put on a technical masterpiece or a really athletic bout. In fact, his physical condition and worsening fitness is the reason for Angle's retirement.
John Cena is an underrated in-ring worker. Almost always, the other guy in his matches runs away with the credit for the matches if they turn out to be great, but very few in the WWE could add drama and stakes to a match as Cena does. He is a fantastic storyteller. So, he will definitely help Kurt Angle tell a great farewell story, possibly of Angle desperately wanting to retire on a winning note.
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The Undertaker is another megastar who has nothing booked for the event yet. However, he is well past his prime, and these two bruised and broken veterans will struggle to put on anything substantial together.