Got an update everyone.  Now this is just estimated launch and subject to change just so everyone knows. But it does appear a 3-way dimmer kit is estimated to launch in May 2021.  

@Carl, appreciate the update on the much anticipated release date of this product. I will personally be purchasing 6 of these once they hit the market. Has there been any updates on beta testers for this product prior to release? Would appreciate being included in this group. Thanks again!

@echo954 

While there is not yet a 3-way dimmer, do you know if the dimmer single-pole and the 3-way Kasa switch can work together (the switch will just be on/off and, when on, the dimmer switch can adjust brightness)?

@echo954 I do not know if the two will work together. My guess is that they will not.

@Carl 

Thank you for an update on this. I am excited about this development!

@echo954 

To anyone looking for a 3-way dimmer setup, there is a way to do it with the regular dimmer switches, on/off will work from either switch....dimming maybe only from one side....unless someone knows a way to automate it...honestly haven't tried that yet....but basically you connect the one switch as normal, Line, load, neutral and ground. Then using the traveler wires parallel the line and neutral wires to the other box connect the switch on the other end with line, neutral, and ground. NO load on this switch. Then through automation set it up so that when one switch turns on it turns on the other, and when it turns off it turns off the other...and vice versa. So only one switch actually operates the load, but through automation both switches stay in sync. Not sure if you can sync up the dim setting through automation as well....probably depends on your setup, I'll update this is I figure that part out. But this might help out some people anyway. 

@JustinG 

I posted a wiring diagram for this exact set-up back in the merry old days of this thread, you can find it here: https://community.tp-link.com/us/home/forum/topic/157607?replyId=409664

You are correct on the automation working for on/off from both switches, but there is of course a bit of a delay from the dummy/non-loaded dimmer.  TP-Link/Kasa has yet to make the dimmer buttons (or even double-press or long-press) as triggers for the automation, so sadly there is no way to link the dimming function between the two switches. So the non-loaded switch might as well be an HS200 (single pole switch).  I've left the HS220 in place in my setup in the hopes that TP-Link will one day enable other trigger events from these dimmers.  

@Carl it's definitely disappointing to hear that there is currently no development of a 3-way dimmer switch. Hell, I'd settle for a switch on one end and a dimmer on the other, considering I rarely ever touch them.

@HamOntNeil 

Look at reply #157.  It should be mid 2021.

I seached through this thread, please excuse me if this was already addressed. 

Can I use a tp link 3 way on one end and a regular 3 way dimmer on the other end?

Do I need a tp link 3 way on both ends, or can I use a regular 3 way switch on the other end?