4) Only one WWE Superstar has won their cash-in but not the title
Of the four failed Money in the Bank cash-in's, two WWE Superstars straight-up lost their matches, one match ended in no-contest, and one man won his match - but not the title. That man was none other than the 16-time world champion himself, John Cena.
To quickly sum up the other situations, WWE Money in the Bank winners Damien Sandow and Baron Corbin lost their matches, ironically John Cena played a part in both matches! Sandow cashed-in his briefcase on the Leader of the Cenation on Monday Night RAW in 2013, trying to capture the WWE World Heavyweight Championship in a losing effort.
Charlotte Flair to return and wrestle a CURRENT CHAMPION?
In 2017, future WWE King of the Ring winner Baron Corbin would cash-in his SmackDown Money in the Bank contract on then WWE Champion Jindar Mahal. However he was defeated via roll-up after he was distracted by John Cena.
Braun Strowman was also unsuccessful in his cash-in attempt after Brock Lesnar interfered in his match against the then WWE Universal Champion during the 2018 Hell in a Cell pay-per-view. Lesnar's attack on both men caused the match to end in a no-contest. Meaning that technically, Strowman didn't lose or win.
On the other hand, John Cena stands alone as the only man to win his match, but not win the championship he was trying to capture. It was 2012, and the backdrop was Monday Night RAW's 1000th Episode. Cena challenged the then WWE Champion CM Punk to a match at the end of the night, using his guaranteed contract.
During the final sequence of the match, the Big Show would attack Cena while he has CM Punk in his signature STF submission hold. Unfortunately for Cena, this caused the match to end via disqualification.
Since Big Show's attack was on Cena, this meant that Cena won the match. However, due to WWE's longstanding rule regarding WWE title matches, Cena could not be awarded the championship. Per the champion's advantage, no championship could change hands due to a DQ.
When you think about it, Cena holds a limitless list of WWE records, he might as well hold this one too.