I just got my 5D Mark IV and I was disappointed to see that LR doesn't support tether for this professional camera 2 months after its release?
Please Adobe... Do not make the same mistake as Apple, consider first professional photographers and their cameras, they are more important customers than smartphone users.
The SDK has been out there for awhile... Capture One tethering was almost immediate once the camera hit the market.
Hope to have this update soon.
You really ought to tell this to Adobe, not to other users in this forum, because we can't help you.
Also, it is my understanding that Capture One writes their own tethering routine, whereas Adobe waits until Canon provides the necessary code, which hasn't happened yet.
Adobe isn't going to make a "special" update for a single camera. If the SDK has been updated and released from Canon then support for tethered shooting could likely be in the next update. There should be an update in the next couple of weeks, I think.