一种解决方法是在每个子任务中添加一个条件检查，以判断是否需要退出任务。具体来说，应该检查一个管道变量，该变量指示是否取消了管道。如果变量设置为真，则子任务退出，并且管道将标记为“已取消”。以下是代码示例：

- job: my_job
  steps:
  - script: |
      # Do some work
      echo "Starting task 1"
      # Check if pipeline is cancelled
      if [ ${{ pipeline.variables.isCancelled }} == 'true' ]; then
        echo "Pipeline is cancelled. Exiting task 1."
        exit 1
      fi
      # Do some more work
      echo "Completing task 1"
    displayName: 'Task 1'
  - job: my_nested_job
    steps:
    - script: |
        # Do some work
        echo "Starting task 2"
        # Check if pipeline is cancelled
        if [ ${{ pipeline.variables.isCancelled }} == 'true' ]; then
          echo "Pipeline is cancelled. Exiting task 2."
          exit 1
        fi
        # Do some more work
        echo "Completing task 2"
      displayName: 'Task 2'
  - script: |
      # Do some work
      echo "Starting task 3"
      # Check if pipeline is cancelled
      if [ ${{ pipeline.variables.isCancelled }} == 'true' ]; then
        echo "Pipeline is cancelled. Exiting task 3."
        exit 1
      fi
      # Do some more work
      echo "Completing task 3"
    displayName: 'Task 3'

在这个示例中，我们将变量 isCancelled 设置为 ${{ canceled() }}，这将返回一个布尔值，指示管道是否被取消。在每个任务中，我们都检查一下 isCancelled 变量，并在必要时退出任务。如果在某个任务中退出了，管道会标记为已取消，并且后续任务将被跳过。这就确保了嵌套任务在取消管道后也会立即退出。