PCIe USB card is an internal hardware expansion card that adds more USB ports to a desktop computer by connecting to a PCI Express slot on the motherboard. These cards provide additional ports, often of newer USB standards like USB 3.0, 3.2, or 3.2 Gen 2, enabling faster data transfer speeds (e.g., 5Gbps, 10Gbps) and higher power delivery for connected devices. They are used to overcome limited onboard USB ports, connect more peripherals, and improve overall system connectivity.