I don’t think dedicated antivirus software is really required anymore. I haven’t run third-party AV software on any of my systems in the last decade.

On Windows, the built-in Windows Defender is good enough for most use cases. When it first launched Defender had a pretty bad track record at stopping viruses, but now it routinely ranks at the top.

On Linux, antivirus software has never really been required. One major exception I can think of would be if you’re running a file server or mail server that talks to OSX or Windows systems. Even then the AV software isn’t really there to protect the server, it’s there to make sure you don’t pass malware or viruses to those non-Linux clients.