Genshin Impact is an action role-playing game developed by a Chinese Developer, miHoYo, and it is also free to play. One of the main reasons why this game becomes popular/booming is because the dev of this game is also the one who makes Honkai Impact 3D.
And there is no doubt that the latter already gained so much popularity.
Both of the games heavily relied on their fantastic character visuals with Genshin Impact offers something more, which is its open-world feature.
According to some sources, Genshin Impact received a reasonably positive reception at release, with journalists praising the open world direction and the combat; however, criticisms were raised at its monetization.