Whole life critical illness insurance carries savings component. If the insured does not make any claims, there will be cash value when surrendering the insurance. In general, whole life critical illness insurance has broader coverage, covering more diseases and some for multiple times.
On the contrary, without having savings component, term life critical illness insurance offers pure protection and needs to be renewed every fixed term (e.g. every 5 years or 10 years). The coverage period of term life critical illness insurance is generally up to around age 80.