In his latest tweet featuring the new mascot, the Metal Gear Solid series creator said (sorry the translation is a bit rough): 

This is the Kojima production of icon “Ludens (play man)”. State-of-the-art equipment and technology, by making full use of the frontier spirit to the “new future”, I would like to deliver a “new play”. He’s wearing is a spacewalk (EVA) creative clothing.

This full image of “Ludens” was attached (click it to zoom in):

Clearly Kojima and the crew at Kojima Productions are looking toward new experiences, while still trying to keep the spirit of the games which came before.