WireGuard - a VPN runs as a module inside the Linux kernel

WireGuard is an open-source software application and protocol that implements virtual private network (VPN) techniques to create secure point-to-point connections in routed or bridged configurations. It is run as a module inside the Linux kernel and aims for better performance than the IPsec and OpenVPN tunneling protocols.

Reference:

https://en.wikipedia.org/wiki/WireGuard