To use Caido to intercept (and tamper with) your https traffic, it is necessary to import and trust the CA certificate of Caido in your browser.
After starting Caido on your machine, navigate to
localhost:8080 (or the port you've configured for Caido to listen to) and log in.
Open the "User Dropdown Menu" in the top right
Navigate to "CA Certificate" or click here.
Download the Certificate and follow the instructions to import and trust it in your browser of choice.
After you've successfully imported the certificate, you are good to go and can configure your browser to proxy it's traffic through Caido.