Question about Xiaomi MI TV Stick 4K

Text on MI com: With the built-in Chromecast, you can easily cast videos or other content from your phone, tablet or laptop directly to your TV screen in 1080P.

It is not clear what kind of laptop with which operating system you are using, whether you have WiFi at home, etc.

Depending on the device, certain requirements must be met:
Windows 10/11: Software on the laptop e.g. Chrome Browser, Microsoft Edge Browser or suitable software that can stream to Chromecast.

Apple OSX: Suitable software such as AirBeam TV

It is best to enter the following on youtube: How to Use Screen Mirroring on Xiaomi Mi TV Stick | Chromecast Built-in

Yes, Cromecast is integrated. If the PC can do that, then it works.