While the CIA triad provides the defense, represent the high-end of the offensive spectrum. An APT is a sophisticated, long-term, and targeted cyberattack where an intruder gains access to a network and remains undetected for an extended period. Key Characteristics of APTs: What is the CIA Triad and Why is it important? - Fortinet
If you have a PDF that promises to take you from CIA to APT, here is the roadmap it should follow: from cia to apt an introduction to cyber security pdf