query GetMSTeamsMembersForChannel($msTeamsChannelId: ID!, $msTeamsTeamId: ID!) {
  getMSTeamsMembersForChannel(msTeamsChannelId: $msTeamsChannelId, msTeamsTeamId: $msTeamsTeamId) {
    members {
      id
      roles
      displayName
      visibleHistoryStartDateTime
      userId
      email
    }
  }
}

{
  "msTeamsChannelId": "id",
  "msTeamsTeamId": "id"
}

{
  "data": {
    "getMSTeamsMembersForChannel": {
      "members": [
        {
          "id": "id",
          "roles": [
            "guest"
          ],
          "displayName": "string",
          "visibleHistoryStartDateTime": "string",
          "userId": "id",
          "email": "string"
        }
      ]
    }
  }
}