The anti-malware software provided by Microsoft 365 (from their website) provides for:
1) Automatic scans of the environment
2) Periodic scans of the file system (at least weekly)
3) Real-time scans of files as they are downloaded, opened or executed
4) Automatic download and application of signature updates at least daily from the vendor's virus definition site
5) Alerting, cleaning, and mitigation of detected malware