curl --request GET \
  --url https://api.coinbase.com/api/v3/brokerage/cfm/positions/{product_id}

{
  "position": {
    "product_id": "<string>",
    "expiration_time": "<string>",
    "side": "<any>",
    "number_of_contracts": "<string>",
    "current_price": "<string>",
    "avg_entry_price": "<string>",
    "unrealized_pnl": "<string>",
    "daily_realized_pnl": "<string>"
  }
}