What kind of devices you're using it with?
Just tried putting my TB2->TB3 adapter at clover screen, and it still doesn't show up in USB devices, unlike my Z370N desktop where it works fine on USB-C port. Waiting for TB3->DP and TB3->Ethernet+USB adapters to arrive, to test them.
... 10 minutes later ...
OMG! IT WORKS! Thank you!!!
Since XPS port is TB3, and Z370N is USB-C 3.1, devices are being shown in different sections of system information app.
Z370N shows it under USB, and XPS shows it under PCI. And I can finally use my Apple TB2 Gigabit Ethernet adapter!
Doesn't work for miniDP though. Apparently, this TB3->TB2 adapter is for USB devices only.