There are no known Windows-like Viruses in the wild that self replicate and affect macOS, because of the underling UNIX Foundation and Permission Limitation.
The The Built in Security is all that is required to protect the computer.
Should “ Certain & Specific Software “ referenced from above be installed - it will negatively impact macOS. It is suggested, to download directly from a respected ASC Contributor, the application Malwarebytes for Mac.
It is free or paid for added features.
Disclaimer: I am not affiliated with nor receive compensation from the Developer.
Run the Application and it should remove the malware / adware. Once done, restart computer and test.