Google tends to release new Chromecast models only sparingly (you can still buy a years-old 1080p unit today), but it may be more aggressive with the Google TV model. 9to5Google sources claim the company is already developing a new Chromecast with Google TV. Documentation and code sleuthing have reportedly revealed the codename "Boreal," while 9to5 understood the Android TV media hub would launch later in 2022.
The purported leak doesn't mention specifications, although newer processing power with broader video support might be necessary. XDA and others have heard Android TV will require AV1 video format support after March 31st, and that's conspicuously absent on the existing Chromecast with Google TV. The company might also use the opportunity to address common complaints, such as the modest storage.
Provided the leak is accurate, the question is whether or not this is a straightforward replacement for the existing Chromecast or a higher-powered separate model. Given that the existing Chromecast already supports 4K HDR, though, a replacement seems more likely. It's clear any changes would be substantial enough to warrant a new internal nickname — Google doesn't typically hand out names for minor revisions.