sensitisation vs immunisation

sensitisation and immunisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
sensitisation	Yes	No	No	No
immunisation	Yes	No	No	No

As nouns, immunisation is a hypernym of sensitisation; that is, immunisation is a word with a broader meaning than sensitisation:

sensitisation: rendering an organism sensitive to a serum by a series of injections
immunisation: the act of making immune (especially by inoculation)

Other hypernyms of sensitisation include immunization.

sensitisation (noun)	immunisation (noun)
rendering an organism sensitive to a serum by a series of injections	the act of making immune (especially by inoculation)
(psychology) the process of becoming highly sensitive to specific events or situations (especially emotional events or situations)
the state of being sensitive (as to an antigen)