He was going to main event a PPV (No Mercy) after whooping 24 PPVs. And the presidential debate couldn't let him main event this time. The last Cena main-evented a PPV was Survivor Series 2014.
Here is the full list of every single PPV main event in that time span.
Dean Ambrose vs Bray Wyatt (TLC 2014)
Royal Rumble match (Royal Rumble 2015)
Daniel Bryan vs Roman Reigns (Fastlane 2015)
Brock Lesnar vs Roman Reigns (WrestleMania 31)
Seth Rollins vs Randy Orton (Extreme Rules 2015)
Seth Rollins vs Orton vs Ambrose vs Reigns (Payback 2015)
Seth Rollins vs Dean Ambrose (Elimination Chamber 2015)
Seth Rollins vs Dean Ambrose (Money in the Bank 2015)
Seth Rollins vs Brock Lesnar (Battleground 2015)
Brock Lesnar vs The Undertaker (SummerSlam 2015)
Seth Rollins vs Sting (Night of Champions 2015)
Brock Lesnar vs The Undertaker (Hell in a Cell 2015)
Roman Reigns vs Dean Ambrose (Survivor Series 2015)
Sheamus vs Roman Reigns (TLC 2015)
Royal Rumble match (Royal Rumble 2016)
Brock Lesnar vs Reigns vs Ambrose (Fastlane 2016)
Triple H vs Roman Reigns (WrestleMania 32)
Roman Reigns vs AJ Styles (Payback 2016)
Roman Reigns vs AJ Styles (Extreme Rules 2016)
Roman Reigns vs Seth Rollins (Money in the Bank 2016)
Dean Ambrose vs Rollins vs Reigns (Battleground 2016)
Brock Lesnar vs Randy Orton (SummerSlam 2016)
Dean Ambrose vs AJ Styles (Backlash 2016)
Kevin Owens vs Seth Rollins (Clash of Champions 2016)
And now Bray Wyatt Vs Randy Orton (No Mercy).
Reigns is the leader out of Shield with 10 PPVs. Rollins-9 and Ambrose- 8.
It does signify that Cena is more towards part-timing wrestling in WWE.
Here is the full list of every single PPV main event in that time span.
Dean Ambrose vs Bray Wyatt (TLC 2014)
Royal Rumble match (Royal Rumble 2015)
Daniel Bryan vs Roman Reigns (Fastlane 2015)
Brock Lesnar vs Roman Reigns (WrestleMania 31)
Seth Rollins vs Randy Orton (Extreme Rules 2015)
Seth Rollins vs Orton vs Ambrose vs Reigns (Payback 2015)
Seth Rollins vs Dean Ambrose (Elimination Chamber 2015)
Seth Rollins vs Dean Ambrose (Money in the Bank 2015)
Seth Rollins vs Brock Lesnar (Battleground 2015)
Brock Lesnar vs The Undertaker (SummerSlam 2015)
Seth Rollins vs Sting (Night of Champions 2015)
Brock Lesnar vs The Undertaker (Hell in a Cell 2015)
Roman Reigns vs Dean Ambrose (Survivor Series 2015)
Sheamus vs Roman Reigns (TLC 2015)
Royal Rumble match (Royal Rumble 2016)
Brock Lesnar vs Reigns vs Ambrose (Fastlane 2016)
Triple H vs Roman Reigns (WrestleMania 32)
Roman Reigns vs AJ Styles (Payback 2016)
Roman Reigns vs AJ Styles (Extreme Rules 2016)
Roman Reigns vs Seth Rollins (Money in the Bank 2016)
Dean Ambrose vs Rollins vs Reigns (Battleground 2016)
Brock Lesnar vs Randy Orton (SummerSlam 2016)
Dean Ambrose vs AJ Styles (Backlash 2016)
Kevin Owens vs Seth Rollins (Clash of Champions 2016)
And now Bray Wyatt Vs Randy Orton (No Mercy).
Reigns is the leader out of Shield with 10 PPVs. Rollins-9 and Ambrose- 8.
It does signify that Cena is more towards part-timing wrestling in WWE.