The following sensitive information about employees may be included in the internal emails of the company's HR department: 1. **Personal information**: including name, address, phone number, email address, date of birth, etc. 2. **Salary information**: employee's salary, bonus, performance evaluation and other salary-related information. 3. **Employment history**: employee's work experience, position change, promotion, etc. 4. **Attendance records**: employee's attendance, leave, overtime, etc. 5. **Health information**: medical conditions, sick leave and other health-related information of employees. 6. **Background investigation results**: including criminal records, credit records and other related investigation results. 7. **Training and development**: employee's training records, career development plans and related evaluations. 8. **Disciplinary actions**: employee's performance issues, warnings, disciplinary action records, etc. 9. **Resignation information**: information about the reasons for employee resignation, resignation arrangements and related steps. 10. **Complaints and disputes**: complaints, disputes and handling between employees or between employees and management. Due to the sensitivity of this information, the HR department must be extra cautious when sending internal emails and ensure that relevant privacy protection policies and regulations are followed.