How to bind one key to multiple commands in VSCode

There's a new way to achieve this without an extension:

1. Run "Tasks: Open User Tasks" command to create or open a user level tasks file.

2. Define commands as separate tasks, like so:

{
    "version": "2.0.0",
    "tasks": [
        {
            "label": "ctrlUp1",
            "command": "${command:cursorUp}"
        },
        {
            "label": "ctrlUp2",
            "command": "${command:scrollLineUp}"
        },
        {
            "label": "ctrlUpAll",
            "dependsOrder": "sequence",
            "dependsOn": [
                "ctrlUp1",
                "ctrlUp2"
            ],
            "problemMatcher": []
        }
    ]
}

3. In your keybindings.json:

{
    "key": "ctrl+up",
    "command": "workbench.action.tasks.runTask",
    "args": "ctrlUpAll",
    "when": "editorTextFocus"
}

("ctrlUpNNN" label format chosen for readability, task labels can be anything).

This is currently not possible, but the corresponding feature request is tracked here. However you should take a look to the macros extension. It enables you to chain different commands to a single custom command. This custom command then can be bound to a hotkey. In your case you could add this to your settings.json:

"macros": {
    "myCustomCommand": [
        "cursorUp",
        "scrollLineUp"
    ]
}

And then add your custom hotkey to the keybindings.json:

{
  "key": "ctrl+up",
  "command": "macros.myCustomCommand"
}