The error message "CA PAM Client is damaged and can't be opened" appears when trying to install the PAM client on MAC OSX 15 Sequoia using PAM version 4.1.1.
The PAM Client install was attempted from an older release that did not support the newer version of the MAC operating system.
This does require upgrading to a version of CA PAM that has support for the specific version of MAC OS. In this specific case, CA PAM 4.2.1 supports MAC OS 15 "Sequoia".