In a large mixing bowl, whisk together the mayonnaise, apple cider vinegar, granulated sugar, Dijon mustard, celery seed, kosher salt, and black pepper until smooth.
In a separate bowl, combine the apples with the lemon juice, tossing to coat, then add to the dressing.
Add the green cabbage, carrots, and scallions to the bowl.
Toss until everything is evenly coated. Cover and chill 20–60 minutes, until the cabbage softens slightly and the flavors meld. Stir again and serve cold.