This specific area is not my domain but I wondered if any of these would shed some light on the potential differences for you
Apologies if you have them or if they are wrong. We have been wrestling with other aspects of NHS documentation on their APIs which is slightly lacking and in a state of flux especially for their content services data quality.
Good luck, please post the answer here when you find it. We may be required to let the same happen for some of our services one day
If you currently integrate with CIS1 authentication using the TicketAPI.dll, then you will be able to continue doing this as you have always done (for the moment - see below), and the backend authentication stack has not changed in terms of SAML response etc.
The Identity Agent has supported PIV/CIV card for a couple of years but you should always aim to stay on the latest versions
There is a new middleware for Series 9 smart cards that will be available to download from the WES and available via Microsoft Update.
Any application integrating with the Smart Card via the Gemalto PKCS#11 library (gclib.dll) will no longer work with the Series 9 Smart Card as the use of PKCS#11 has been deprecated for a number of years now. If there is a requirement to perform digital signing with this Smart Card and PKCS#11 is the current approach then, you will need to speak to NHS England to obtain the replacement Digital Signing API.
Also note that the CIS1 auth stack is heading for retirement over the next few years. Applications currently using this should already be looking at moving to the new authentication platform, CIS2 Authentication, which is an OIDC compliant authentication flow, allowing the use of many types of authenticator, including smartcards.