Please note

Xray provides a free plugin for TeamCity capable of integrating both with Xray for Jira server and also with Xray for Jira Cloud.

You may find full instructions and available features/limitations in the page Integration with TeamCity available in Xray for Jira server confluence space.

Please note that whenever using the previous link, you will be redirected to Xray for Jira server documentation site, so please don't forget to come back to the correct documentation site for Xray Cloud.