Hi @pooria, this sounds like you have two separate executions here (one triggered using a webhook node, and another one using the Telegram trigger). n8n’s Merge node is only aware of to the current workflow execution and won’t be able to take previous executions into account.
So you’d have to either
a) persists your session data somewhere (for example in a database) during your first execution, then fetch the required data in your second execution
b) consider using the Wait node where possible (it might not be in your case). The Wait node isn’t just able to wait a specified amount of time, it can also wait for incoming webhooks as shown here.
If you’re running into trouble with this perhaps you can open a new topic and share your workflow along with any other relevant details (such as suitable example data)?