What is Openport.app? Am I being a victim of some hacker? I haven't installed it

OS: 10.15.2 Catalina

If so. Is it safe to remove by command line?
OpenPort is a program used to create a tunnel from your machine to the Internet. Essentially allowing your, or others that are given access, to connect to your machine from the Internet to remote control it, copy files, etc.

It is normally used in situations where the machine cannot be placed directly on the Internet. For example in home user setups your machine can be stuck behind NAT, home firewalls, etc. that makes it difficult to access it from the Internet. OpenPort connects from your machine to a server to create a tunnel that will easier connection from the Internet.

You pay a monthly subscription for the server service for OpenPort, although they have a limited, free plan as well.

If you haven't knowingly installed OpenPort.io, I would uninstall right away. It is safe to remove in as so far that it doesn't come standard with the Mac, so it is an optional extra. You might want to take a backup before removing, if after removing you realize that it was actually yourself that installed the app for some purpose and want it back with your own configuration.