That shield is a drain wire combined with either a woven braid (most effective at lower frequencies) or a solid aluminized mylar foil (most effective at higher frequencies), or, for the best cables, both together.

A USB-C cable really should be shielded. Here's a cross-section I took of a nice full-featured USB-C cable: https://ibb.co/svR5Yvyr . You can see the VBUS/GND (fat red/black), the SS pairs (white plus red/blue/yellow/brown, each one foil shielded on this cable), the USB 1/2 pair (white/green), and then the CC and SBU stuff is the remaining wiring. Notice how not just the whole thing is braid+foil shielded, but the SS pairs are individually shielded; that's really important at these speeds, and what you want to see on a good cable.

Compare with two USB 2.0 cables: https://ibb.co/BHz4v1mx and https://ibb.co/GfpJmgbx ; the first one has the shield braid, as it should, but everything else is nicer on the second one. Cables!