Apple Built A SIM Card That Lets You Switch Between AT&T, Sprint, And T-Mobile 12 years ago
Actually this feature is not Apple exlusive.
I created a little project that allows remote usage of multiple SIM cards as a Software-SIM on MTK based Android phones. Forward the commands via TCP from a modified Baseband-firmware. This means you could e.g. have multiple SIM cards for your business trip without changing the card in your phone. Also malicious people could steal your SIM authentication if you use a vulnerable Android phone and use it: