I believe the two “triggers” are for ICBM launches from Air Force silos....
The USAF uses key switches.
That’s definitely the case for the silos ... two keys, far-enough apart that one person can’t reach both at the same time, and, if I recall correctly, out-of-sight of each other so that one person can’t turn the other key with some sort of stick/tool.
It would appear, at least in the US submarines, that there’s only one “trigger”, but another interlock elsewhere on the boat that requires two people to agree to launch.