Cloning Related Files, Here relating files from related case record to lead

AttachFile.cls

trigger AttachFile on Lead (after insert) {
    List<ContentDocumentLink> cdeInsertList = new List<ContentDocumentLink>();
    System.debug('line3');
    Map<Id, Id> caseId2 = new Map<Id, Id>();
    for(Lead ldItr : Trigger.New) {
        caseId2.put(ldItr.Case__c, ldItr.Id);
    }
    System.debug('line8');
    
    for(ContentDocumentLink cdl : [SELECT 
                                            ContentDocumentId,Id,
                                            IsDeleted,LinkedEntityId,
                                            ShareType,SystemModstamp,
                                            Visibility 
                                         FROM 
                                            ContentDocumentLink 
                                         WHERE 
                                            LinkedEntityId IN :caseId2.keySet()]){
        ContentDocumentLink newCDE = cdl.clone(false, true, false, false);
        newCDE.LinkedEntityId = caseId2.get(cdl.LinkedEntityId);
        cdeInsertList.add(newCDE);
        System.debug(newCDE);
    }

    insert cdeInsertList;
}