Though Kurama has “died” as a result of expending too much chakra in the fight against Isshiki, all hope is not lost. Unlike mortal beings such as Naruto and our other beloved characters, the Tailed Beasts' life force simply dissipates. This does not mean they will be dead forever. In the future, Kurama can reincarnate once enough of his chakra is collected to form his existence. Only then will his physical being be brought into the real world.