A new leak suggest that soon you will be able use Siri to call and send messages with WhatsApp. Off-course this feature will work only on iOS devices. Recently, an explanation shown to users when prompted to give WhatsApp access to Siri.
The upcoming Apple iOS 10 will allow Siri integration into third party apps. Once the feature is integrated into Whatsapp, users can able to make calls or send messages directly using Siri. Uber and Netflix are also working to add Siri into their iOS apps.