Port 137 Traffic to Microsoft 365?

We are looking to create a default deny policy on our network for both inbound and outbound traffic, and I am seeing a lot of outbound traffic to port 137 on many websites associated with Microsoft 365. Port 137 is of course associated with NetBIOS over TCP/IP, an insecure protocol that we have disabled on our network. I would like to block outbound traffic to port 137 completely, but was not sure if there was a legit reason why our machines would need to send traffic to port 137 on Microsoft websites? I question why Microsft would even have that port open.