How do the two ingredients in calcipotriol/betamethasone ointment act in psoriasis?

In calcipotriol/betamethasone ointment, calcipotriol is a vitamin D analogue proposed from in-vitro evidence to promote keratinocyte differentiation and suppress proliferation, while betamethasone is a potent corticosteroid with anti-inflammatory, itch-relieving, vasoconstrictive and immunosuppressive effects, without curing the underlying condition.