A candidates CV can be deleted from the ATS but only if it is uploaded via their profile (not via a job application).
The candidate may create a profile within your ATS and upload their CV or multiple CV’s, in this scenario, the candidate and or a user within your organisation with the relevant permission, will be able to delete the CV if required.
If the candidate applies for a job and they upload a CV as part of the application journey (whether the CV is required or not during the candidate’s application journey) then you will never be able to delete that CV as it is associated with an application.
If the candidate uploads a CV to their profile and then uses the same CV to make a job application, the CV that was uploaded during the profile creation stage will still be visible and available to delete. The CV or CV’s associated with any job application/s (whether it is the same CV used during profile creation or a completely different CV), will still appear on the candidate’s profile, but the applicant or relevant user will only be able to download it, the delete option will not be available.