Check that your graphics card has the latest driver; having an outdated driver can often be the cause of an issue you are experiencing. Also, please check that your system is up to date and that you don't have any pending updates from Windows.

Why does slime rancher keeps crashing on Xbox one?

Most of the time, this is actually an issue with the load screen specifically, and the game is still processing the load of your save file in the background. As a note, if you have other applications or games open on your system, completely closing them may reduce the time you need to wait.

Why do my game keep crashing?

Apps can sometimes crash when the storage space is not adequate. You will have to clear up your storage space by deleting unwanted apps and files. Go to Settings -> Apps to uninstall unwanted apps and games.