Zwave

Neither Z-Wave nor Apple have published any intention to merge HomeKit technology with Z-Wave.

That's not how HomeKit works.

HomeKit is a software framework for connecting different accessories to each other using iPhone or iPad apps. The iPhone and/or iPad communicates with the various accessories or their hubs using Wi-Fi or Bluetooth only. It is up to the various accessory manufacturers to connect their hubs to their respective accessories using the radio protocol of their choice be it Zwave or anything else.

Apple's HomeKit requires using either Bluetooth or WiFi. This is because iPhones, iPads, and AppleTV only have those standards built-in. However this does not itself mean it would be impossible for a Z-Wave compatible device to be used.

As an example the Phillips Hue smart lighting system which is officially HomeKit compatible uses the Zigbee wireless standard for its light bulbs, and of course iPhones etc. do not speak Zigbee. However this is solved by having a 'bridge' device aka gateway act as the intermediary and Phillips make a Hue Bridge to act as the intermediary between a normal computer network and the Zigbee system. The Phillips Hue bridge plugs in to your Ethernet network and you would have that Ethernet network connected to a WiFi network and hence reachable by your iPhones etc. It would also via Ethernet/WiFi be linked to either an Apple TV or iPad and hence also remotely accessible across the Internet via HomeKit.

So, in theory it might be possible for a bridge device to act as an intermediary between HomeKit and Z-Wave. I can say that officially at this point in time there are zero such official bridges between HomeKit and Z-Wave. The nearest solution is a completely unofficial software bridge called HomeBridge which is a free open-source program for Linux.

Since one of the main design goals of HomeKit was to provide much stronger security for home automation than previous systems like Z-Wave have offered it is expected that at some point Apple will actively take steps to kill off HomeBridge. HomeKit officially requires including a special chip to handle device verification and encryption and this chip is as per my example built-in to the Phillips Hue Bridge v2. The Z-Wave protocol has previously been hacked several times.