I am using shopify app/store and storefront API . storefront API working fine "ADD cart" "remove cart" . but it is not sync with shopify app/store . why ?

I am using react , graphgql example. In all example are working . but it is not syn with shopify theme/store.

https://github.com/Shopify/storefront-api-examples

In other words when I am adding a item in "CART" API return 200 but it is not adding shopify theme application.It should be sync with shopify store or when I open my application home page it should should one item added in cart