The meat of the story for those of you of a TLDR persuasion is that now Navi 10 (the RX 5700) is out the door there is supposedly a larger and more powerful card on the way, the Navi 23. This is the card described as the 'Nvidia Killer', a hulked out behemoth intended to go head to head with the RTX 2080 TIs and the other very high end GPUs that inhabit territory that Nvidia has largely claimed for itself in recent years. There is no word on any specification for this hypothetical card.
If AMD do have a serious high-end contender up their sleeves for release relatively soon it would be fascinating. The RX 5700 is a big, hardworking, bruiser of a GPU, as evidenced by how many 2.5 slot custom coolers we are seeing, and so taking something like that to the top level of performance could require some truly formidable engineering.
Or it could all just be rumours. We’ll find out one way or the other eventually.