It's antivirus*
And yea it's up to you to install a secondary antivirus software.
Majority of the users are happy with the built-in Windows defender antivirus software.
Anti malware, antivirus, and a firewall program. Normally they are designed to take over the windows version when active and will do so when you install. For example zone alarm shuts down defender when its installed and active but if you shut it down defender kicks back in. This reduces conflict.
I haven't used one since the xp era. Which was before I was born. So from when I learned to actually reinstall the os and keep it maintained, I didn't use one. There is no need. The only viruses my siblings or friends would get is the king of "pc speed up software" that does fuck all.
I haven't used a anti virus program on my windows 10 pc for years and never had a virus/malware issue. Just don't download random things and visit sketchy websites
Based on the fact that you're asking if you should most likely means yes. I haven't needed one since 2001 but I know what they look like installed running through services and so forth. So if you game and don't know what a virus looks like until its running crazy then yes.