You certainly need anti malware and anti adware protection like AdBlock, Ghostery or Malwarebytes but other than that it's up to you.
The MacOs contains it's own protection and it is suggested that using additional security software can adversely affect performance.
If you google 'software protection for Macs' you will get an awful lot of contradictory advice and you really will have to make your own mind up.
I only have AdBlock and Ghostery and I have never had an issue.
One of the main problems is that viruses are often confused with malware/adware and it is suggested that there are currently no viruses in the wild that can infect your Mac.