App Design with 3rd party API integration

I'm in the early stages of building an app that consumes data from a 3rd party API. I'm pulling player statistics / data and building dashboards for each user. There are more than 500,000 players so it will be alot of data. For some users the data will remain unchanged for a significant amount of time others, the data will need to be fetched and updated.

How would you "cache" the results of API calls? I can obviously dump it in the DB, is there another more efficient method?