Certificate schemes can be designed to have defined certificate dependencies in order for certificates within the scheme to remain valid.
A real-world example is that a driver's insurance certificate is only valid if the car also has a valid MOT and the driver has a valid driver's license. In this case the insurance certification scheme would have dependencies defined that the thing (car) must have a valid MOT certificate and the user (driver) must have a valid driver's certificate (license). If these two conditions (dependencies) are not met, the insurance certificate is no longer active (valid).
On the scheme settings... more details to follow
On the certificate detail page, if a certificate has any dependencies, these can be seen by... more details to follow