International human resource management involves three key dimensions: HR activities, types of employees, and countries of operation. There are several types of employees in an international context, including parent country nationals (PCNs), host country nationals (HCNs), and third country nationals (TCNs). Domestic HRM differs from international HRM in that IHRM requires more HR activities like managing expatriate taxation and relocation. IHRM also requires a broader perspective to manage diverse international issues and greater involvement in employees' personal lives when working internationally. The emphasis of HR activities may also change as the mix of expatriates and local employees varies over time.