Create a new scenario in Make (formerly Integromat).
Add the Slack > Get Messages trigger and select the Slack channel you want to monitor.
Add the Telegram > Send Message action.
Enter the message you want to send on Telegram.
Run the scenario.
If you use Slack for work, you can use this scenario to get notifications of new messages on Telegram. This can be useful if you need to be able to respond to messages quickly, even when you're not at your computer.