Busy on busy is a handy Microsoft Teams feature that offers additional call management options.
Admin can configure busy on busy configs for all the users or only for particular users.
Keep in mind that this setting is off by default.
If you want to enable it, tweak the calling policies.
The caller will get a busy tone.
On the other hand, the call recipient will only get a Missed callnotification.
In this manner, theres no pressure to quickly end the call to accept a new one.