https://www.techradar.com/news/nintendo-is-finally-bringing-cloud-saves-to-switch-but-itll-cost-you

While it's generally a console beloved by those fortunate enough to own one, the Nintendo Switch has always had a glaring flaw in its lack of save data backup options. Basically, if your Switch dies, so does that Breath of the Wild save file you've sunken hundreds of hours into. 

Thankfully, that won't be the case for long, as the house that Mario built has officially revealed that 'Save Data Cloud Backup' functionality is coming to the console as part of its long-awaited Nintendo Switch Online service. Yes, that means you'll have to subscribe in order to back your games up.