<?php
use Microsoft\Graph\Beta\GraphServiceClient;
use Microsoft\Graph\Beta\Generated\Teams\Item\InstalledApps\Item\TeamsAppInstallationItemRequestBuilderGetRequestConfiguration;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestConfiguration = new TeamsAppInstallationItemRequestBuilderGetRequestConfiguration();
$queryParameters = TeamsAppInstallationItemRequestBuilderGetRequestConfiguration::createQueryParameters();
$queryParameters->expand = ["teamsAppDefinition"];
$requestConfiguration->queryParameters = $queryParameters;
$result = $graphServiceClient->teams()->byTeamId('team-id')->installedApps()->byTeamsAppInstallationId('teamsAppInstallation-id')->get($requestConfiguration)->wait();