Ok, let's start with asking some broad spectrum questions
1.) Is it a Teams Meeting or 1:1 call, or both? 2.) Is it VOIP Call, PSTN Call, or both? 3.) Is it an external mic, or built in? If external what brand/model is it? 4.) If it is external mic have you tried disconnecting/reconnecting, latest drivers 5.) Does it occur on a test call (via settings)? 6.) Is Teams Client updated to latest version? 7.) Have you tried uninstalling/reinstalling Teams? 8.) What if someone hard mutes you in a meeting?