The image features an orange crab and Hummer EV inscription, which suggests that the company wants to underline its undisclosed yet Crab mode, listed previously among features.
Crabs are known for being agile and moving not only forward and backward, but also sideways, so it must be related to this motion we guess. Especially with the description "Real revolutionaries forge their own direction. #GMCHummerEV". Own direction?
It's difficult to guess whether the Crab mode is just turning in place (like the Rivian Tank Turn) or maybe it's combined with rear steering wheels.
The GMC Hummer EV will be unveiled this Fall. Then we should know more. The production at the Detroit-Hamtramck Assembly is scheduled for Fall 2021, at least if nothing goes sideways...