Cannon see subcategory in permalink

Good question.

WordPress determines the permalink by finding the category closest to the root.

  • If the parent category is selected (or if both the parent category and the child category are selected), then the permalink will only include the parent category.
  • If only the child category is selected, then the permalink will include the parent category followed by the child category.

So, for your case, be sure to select only the child category.