Why does my USB C hub get hot?

Heat is normal for USB C hubs, especially when driving a 4K display, charging a laptop, and transferring data simultaneously. Aluminum hubs run warmer to the touch because the metal acts as a heatsink this is actually good, as it means heat is being dissipated rather than trapped inside. If your hub gets hot enough to be uncomfortable, try reducing the workload or ensuring it has airflow around it.