Those who have heard and read Cyber Kill Chain may not be aware that various organizations [Gartner, LockHeed, Varonis, SANS] mention it with slight variants. That might confuse you when you assume there is only one Cyber Kill Chain model. Again when you learn about MITRE ATT&CK, it might further confuse you how MITRE ATT&CK fit in those models. One of the reasons why they can be so confusing to new learners with Penetration Testing background is because they are more or less derived from a typical Penetration Testing workflow. Anyone with Penetration Testing background could be bluffed by them with new terms (“model”, “kill chain”, “weaponization”).