A recent change to Teams search means that matching files are included in the autosuggested list generated as users type in search terms. It’s a small but good change. The files data comes from SharePoint Online sites the user can access and their personal OneDrive for Business account.
The standard Teams search function can unearth a lot of information in chats and channels. Using filters, precision searches, and contextual searches makes it easier to find what you need, even if you might have to learn some new tricks. But life is full of new experiences, and so is search.