Here's how we can proceed, follow the instructions below:

In your previous task, depending on whether you're using Python or Scala, set the task value like this:
dbutils.jobs.taskValues.set("check_value", "2")

In your if-else task, you must reference the name of the previous task as follows:
{{tasks.['previous_task'].values.['check_value']}}

Please review the attached screenshot for further clarification