SSO between SAP Webgui for HTML and SAP Cloud platform Extension application

wanted to achieve SSO between SAP Webgui for HTML of On prem. S/4HANA system ,and between SAP cloud platform extension application ,Application open webgui in new window but prompt user and password ,how SSO can be achieved in this scenario between Cloud platform Sub-account and SAP webgui,any suggestions or documentation will be very helpful.