reactjs – Can’t normalize response graphQl (ApolloClient)

I would to normalize GET_NATIONS_LIST response query.
I’m using React and GraphQl with the client Apollo.

My query GET_NATIONS_LIST:

export const GET_NATIONS_LIST = gql(`
    query getNationsList{
        nationsList{
            acronyms
            description
        }
    }
`)

My graphQl configuration:

export const GRAPHQL_CLIENT_CONFIG = {
     link: from([errorLink, new HttpLink({uri: '/graphql'})]),
     cache: new InMemoryCache({
         typePolicies: {
            Query: {
                fields: {
                    nationsList:(existing, options)=>{
                        console.log("existing",existing) //it print the right response

                        return existing?.map(nation=> ({
                            label: nation?.acronyms,
                            value: nation?.description
                        })
                    }
                }
            }
        }
   })
}

The console log “existing” print the right response but the return don’t update cache.
How can I normalize query response ?