Pinterest API to retrieve related search queries ( GET https://api.pinterest.com/v3/search/typeahead/?num_recent_queries=10&q=bos&tags=recent_queries&access_token=APIKEY )

pinterest_related_search.json

{
    "status": "success",
    "code": 0,
    "message": "ok",
    "data": [
        {
            "vertical": "pins",
            "tag": "recent_queries",
            "link": "/search/pins/?q=boston historical&rs=rs",
            "query": "boston historical",
            "type": "recent_query",
            "id": "boston historical"
        },
        {
            "vertical": "pins",
            "tag": "recent_queries",
            "link": "/search/pins/?q=boston history&rs=rs",
            "query": "boston history",
            "type": "recent_query",
            "id": "boston history"
        }
    ]
}

More information on this here.