CGT is a tax on assets sold or gifted IHT is a tax on the diminution of value.
IHT on PET’s – gifts to individuals is exempt as long as the individual lives 7 years. That same asset gifted will therefore be taxed to CGT unless gift relief can be claimed.
You cannot pay tax twice on the same transfer/gift. So when someone dies IHT is the prominent tax and therefore CGT is not applicable.
It is very important that you do not get these two taxes mixed up – learn each one carfeully