Over the last decades, different polymers have been employed as a material for fabrication of selective membranes for gas separation. Today, some of these membrane materials have been commercially consolidated as polymer-matrix; however, the need to improve the performance of polymeric gas separation membranes above Robeson's upper bound has conducted the development of mixed matrix membranes (MMMs). One of the most recent approaches is the use of polymers of intrinsic microporosity (PIM), which seem to provide high permeability using different composites as fillers dispersed into the polymer matrix. The aim of this work is to provide a brief overview of the current studies on developments of new MMMs by using PIMs. These recent studies are also summarized and discussed according to the main applied filler, techniques used for characterizing the membranes, and the highlighted remarks in the studies. Finally, it denotes the prospects and future trends of membrane applications in this field.