#1 Undertaker
The Undertaker could be a perfect opponent for John Cena at WrestleMania 35. Presently, He is a part-time performer, and he wrestles only a few times a year. Undertaker's last WWE appearance was at Crown Jewel where he teamed up with Kane to face DX.
The Undertaker has immense popularity, and he is regarded as one of the greatest wrestlers in WWE history. The Phenom has a long list of achievements, and he has won several titles in his career.
Undertaker won the hardcore title once, tag team title 7 times, and the WWE title 7 times. Undertaker has also won the Royal Rumble match once, in 2007. Nevertheless, his most noteworthy achievement was the WrestleMania streak, which was broken by Brock Lesnar at WrestleMania 30. Currently, his Wrestlemania record is 24-2, and his other loss came against Roman Reigns.
Cena faced Undertaker at WrestleMania 34, and The Undertaker won within three minutes. The storyline did not have a proper build up, and it could continue this year. The Undertaker is in the twilight of his career, and Cena could be the perfect opponent to retire him at WrestleMania 35.