Participants have not been made official as of yet, but wrestlers such as Ricochet, Cesaro, Andrade, Apollo Crews, Samoa Joe, and Ali were visible in the advertising.
The King of the Ring has not been used since 2015, when quarterfinal matches took place on the April 27 edition of Raw, and the final rounds followed up the next night on WWE Network. Wade Barrett won that year's tournament, defeating Neville in the final round.
Assuming this tournament is composed into that one singular episode of Raw, this would mark the third time that the tournament was a Raw exclusive, following 2008 and 2010. Those tournaments were won by William Regal and Sheamus, respectively.
The King of the Ring began in 1985 as a house show gimmick, held most years through 1991. It was revived in 1993 as an annual pay-per-view, bridging the gap between WrestleMania and SummerSlam until it was discontinued in 2002. The tournament was also brought back in 2006, which wrapped up at the Judgment Day pay-per-view when Booker T won in the finals.