Canon's “look what we can do” zoom, the RF 28-70mm f/2L USM is about as highly regarded as any standard zoom lens in history of consumer optics.
We have been told that a sequel for the RF 28-70mm f/2L USM is already in the works, without a mention of when we may see it.
The source claims they will be able to squeeze further optical performance out of the lens design as well as “significant” weight reduction. The weight reduction would definitely be welcomed for a lot of people that love the current lens.
If weight reduction is a big part of the design, I don't image we'll see image stabilization added to the RF 28-70, and IBIS does a great job when shooting with this lens.
We do think that Mark II versions of some of the early RF mount lenses will definitely be coming in the next year or two. The RF 70-200mm f/2.8L IS USM is rumored to be getting an internal focus design follow-up this year.