If your Type-C USB 3.0 3-in-1 Combo Hub (ST-TCUHM) is not being detected, start with the connection itself and the LED on the hub, since the LED turns on whenever the Type-C USB 3.0 3-in-1 Combo Hub is plugged in correctly. This hub adds USB-A ports plus an SD and microSD card reader to a USB-C port, and only one card slot can be read at a time.

How to fix detection problems with the Type-C USB 3.0 3-in-1 Combo Hub

1. Seat the USB-C connector fully into the USB-C port on your computer, then check the LED on the Type-C USB 3.0 3-in-1 Combo Hub. If the LED is off, the hub is not making a solid connection.
2. Try a different USB-C or Thunderbolt port on the same computer.
3. Unplug and reconnect the Type-C USB 3.0 3-in-1 Combo Hub. To unplug it, pull the top side gently in the direction opposite the connector rather than yanking it straight out.
4. Check whether the hub appears in System Information under USB on a Mac, or in Device Manager on Windows.
5. Use one card slot at a time. Only one card can be read at a time on the Type-C USB 3.0 3-in-1 Combo Hub, so the SD slot and the microSD slot will not work together.
6. Push the memory card in until it clicks fully into place, then check Disk Utility on a Mac or Disk Management on Windows to see whether the card appears but is unformatted.
7. Test a USB device directly on your computer first to confirm the device itself works, then try a different USB device in the same port on the hub.
8. Set the right expectation for charging. The USB-A ports on the Type-C USB 3.0 3-in-1 Combo Hub are mainly for data transfer. They can charge an iPhone, but they do not supply enough power to charge an iPad.
9. Restart your computer fully, then reconnect the Type-C USB 3.0 3-in-1 Combo Hub and test again.
10. Test the Type-C USB 3.0 3-in-1 Combo Hub on a different computer to confirm whether the issue is the hub or the host device.