USB-C to Displayport cable or adapter
Use a Type C DisplayPort cable.

The ports on your MacBook Pro are Thunderbolt 3 which is a multiplexing of multiple signals:


PCIe
USB 3.1
DispayPort
Power


Since it natively supports DisplayPort, you want a cable, not an adapter.

Difference between cable and adapter


A cable is just an interconnect between a source and an end device using the same signaling
An adapter creates a signal from one to another (from USB to DVI or HDMI)


In this case, a cable is "better" because it's not converting any signals.  Less conversion means better reliability.