Chassis having an insertion key assembly for a pluggable module

Example implementations relate to an insertion key assembly for a pluggable module. The insertion key assembly includes a stopper element having a stopping tab, a biasing element, and a driver element having a driving tab. The biasing element is connected to the stopper element and the driver element. In a relaxed state of the biasing element: i) the stopper element is pushed outwards by the biasing element to protrude the stopping tab into a passageway defined by a plurality of walls of a chassis, to block insertion of the pluggable module inside the passageway, and ii) the driver element is pushed outwards by the biasing element to protrude the driving tab into adjacent passageway. In a biased state of the biasing element, the stopper element is pulled inwards by the biasing element to retract the stopping tab from the passageway to allow insertion of the pluggable module inside the passageway.