Some useful information already given in this thread, whilst I think an Anti Virus not strictly necessary will depend on preference and need (depending on if you use apps outwith offical sources) and advice is always to take care in these situations. The inbuilt Knox security is said to protect against malware/malicious threats and McAfee Anti Virus is on board should you wish to use it. https://www.deccanchronicle.com/technology/mobiles-and-tabs/220618/samsung-knox
However outside the established names many Anti Virus apps on the Play Store are at best ineffective. https://www.extremetech.com/mobile
I believe samsung is a big and great brand and a love them alot i have used my samsung device to access the Old Mobile Bet9ja which makes easy based on the fact of what i do for a living everyday.
You should download anti-virus software for your device. Any device needs to be protected. And if you use the android os platform, you should download it at the TaiAppMod.