Mobile Mario Kart Tour from Nintendo has now been out for a few days on iOS and Android devices. The game is what you expect: a mobile Mario Kart game. The game is free-to-play, so it has microtransactions and restrictions on how much you can play at a time. This is quite common for mobile games.
What is not that common, however, is the fact that the game features a monthly subscription service. The first 2 weeks are free, and by paying $4.99 a month you can play 200cc races, and get more challenges and gifts when playing. You can read more about the subscription service here.