For use on [story-identification] questions about the sub-genre of Japanese works "Isekai". Always use with the media tag when known, for example, [novel], [manga], [anime], [video-games], etc.
Isekai is a Japanese fantasy subgenre, featuring a protagonist being transported to — or possibly trapped in — a parallel universe or fantasy world. Common plot points range from them finding a gateway to the other world, being summoned as chosen heroes, or being reincarnated into the world after their death, often at the behest of a goddess.
More common in recent manga is for the Isekai protagonist to be aware of their own stats as per the LitRPG phenomena.
A well-known example is the film Spirited Away.