This is the CodeSystem that contains all the codes in International Classification of Diseases, 11th Revision Mortality and Morbidity Statistics (MMS) (http://id.who.int/icd/release/11/mms) and International Classification of Diseases, 11th Revision Mortality and Morbidity Statistics (MMS) (http://id.who.int/icd/release/11/mms). E.g. what you have to deal with if you get resources containing codes in either of them