Question about Lenovo Yoga 520-14IKBR

The Yoga520 has its own USB-C port for charging, so the second USB-C port can be used without adappter confusion.
Thunderbolt is an Apple interface (Apple and Intel). Some features were introduced to the Windows world with USB3.1 with the USB-C connector (see https://www.macwelt.de/ratgeber...).
USB 3.1 hardware will always work on Thunderbolt ports, the reverse is not the case! Thunderbolt 3 hardware will not work on a USB 3.1 port.