Simple put, Apple attempts to provide all the malware
detection and removal you need in Mac OS X.
"Effective defenses against malware and other threats" by
John Galt
https://support.apple.com/en-ca/HT204759
"Avoid phishing emails, fake 'virus' alerts, phony support calls,
and other scams"
https://support.apple.com/en-ca/HT204759
"MalwareBytes Anti-Malware for Mac Removes adware and malware
Revives your Mac." MalwareBytes has a more restrictive filter
for adware than Apple. MalwareBytes has come to be accepted as the
only malware detector you should consider. For those pestered
by browser attacks
https://www.apple.com/business/resources/docs/macOS_Security_Overview.pdf
etrecheck
Run etrecheck. The first five runs are free. Provided a
report on your machines hardware and software. Great for
diagnosing your system. Click on the download link at the
bottom of the screen.
http://etrecheck.com/
Apple on Security:
https://www.apple.com/business/resources/docs/macOS_Security_Overview.pdf