Excel 4 Macros are quite old but still can be run on the current version of Microsoft Excel. A research investigated 160,000 macros from November 2020 to March 2021, 90% of the sample Excel 4.0 documents are identified as malicious. Hackers can use the macros to compromise your and spread their malware in the whole system. We suggest organization to remind their staff not to open the those XLM documents.
For details, please refer to the below link: