Windows Defender, which is the built-in antivirus software in Windows operating systems, can provide basic protection against common threats and malware. However, it may not be enough to provide comprehensive protection against advanced and sophisticated threats, such as zero-day exploits, ransomware, and persistent malware.

It's also worth noting that Windows Defender only provides protection for Windows-based devices, so if you use other devices and platforms, you'll need additional protection for those devices.

Therefore, it is recommended to complement Windows Defender with additional security measures, such as using strong passwords, keeping your operating system and software up to date, avoiding suspicious websites and emails, and using a reputable third-party antivirus software. This can provide an additional layer of protection and help ensure that your device and data are protected against a wide range of threats.