Every iteration of Cable has a few problems. Time travel disaster scenarios, a techno-organic virus, and, like, where do I put all these guns, anyway? This concept art from Deadpool 2 gives some insight into the way the film's designers thought through those problems.
In a neat piece of concept art, shared by artist Jerad S. Marantz over on Instagram, we get to see an early design of Cable's arm, and in the process learn a bit about how the film's character designers were thinking about Cable's problems.
What's most interesting here, aside from the wicked arm design, is the explanation for it that Marantz gives. "In order to control the #technoorganicvirus Cable embeds this prosthetic under the virus tech in order to still use it as a functioning arm," he writes.
That's clever! I'm not nearly as up on my techno-organic virus lore as I used to be, but I'm really into the idea of Cable modifying himself to stay one step ahead of the virus, and to keep his arm useful even as it's attacked. Cable's design is a bit different in the final movie — concept art usually is just that, after all — but I'm just going to assume that's the real story with his arm, now. Because it rules.