Nintendo revealed the latest tour for Mario Kart Tour, as well as the fifth wave of Mii Racing Suits.
To begin, on May 4th, 2022, the Doctor Tour will arrive in Mario Kart Tour, bringing with it new characters Dr. Mario and Dr. Luigi. On the same day, the 5th wave of Mii Racing Suits will be introduced to the game, including a Wario-themed costume.
— Mario Kart Tour (@mariokarttourEN) April 29, 2022
According to the teaser at the conclusion of the Wave 5 video, the next Mii Racing Suit wave will be released on May 17th. More information will be released when it becomes available.
About Mario Kart Tour
Mario Kart Tour is a Mario Kart series mobile game. It, like Super Mario Run, is available for free on the App Store and Google Play.  Unlike Super Mario Run and Dr. Mario World, the game extensively features a free-to-play microtransaction structure, including gacha components in the form of objects thrown out of pipes.
Many elements from Mario Kart 7 and Mario Kart 8 are reused, as are gameplay concepts including gliding, underwater driving, and character-specific special items. Furthermore, the game offers various new aspects to the Mario Kart genre, such as reversed courses, trick courses, and the ability to deploy a huge number of any item, including Spiny Shells and Bullet Bills, during a race.