Contact, lead, and person account are three objects that will have the individual field available for tracking data privacy information when data protection and privacy is enabled for an org. The individual object is an object that stores data privacy preferences and requests for customers who are subject to privacy regulations such as GDPR; it can be linked to contact, lead, or person account records using the individual field. Case and opportunity, account and user, or individual, user, and account are not combinations of objects that will have the individual field available for tracking data privacy information; they either do not store customer data or do not support individual object relationships.References:https://help.salesforce.com/s/articleView?id=sf.
individual_object.htm&type=5