I know for example, the Swiss Franc has changed its appearance over the years (the 9th series from that has unveiled since 2016 is currently valid today) although they’re issuing a 10th series set to launch sometime in 2030. The Euro is also considered on being redesigned today (the 2002 original is becoming rarer, while the 2013-19 series is currently in circulation with the removal of the 500€ note capping it at 200€).
That begs the question, why has US Dollar remained the same for so long even though it has changed with little detail (it looks bland as hell in comparison to the Swiss Franc) except adding watermarks, the 90s $100 bill is black and white, the 2009 redesign added a security strip and a quill but Franklin is still depicted. Swiss Franc gets redesigned every 10-15 years, the last time US Dollar was redesigned was around 2004-13.
I live in Scotland which has 4 different types of notes circulating at the same time, all have been replaced over time as to prevent forgeries and are currently very secure. US Notes are known for being insecure as fuck which causes significant losses to retailers and loss of confidence in cash transactions. Its honestly a bit of a joke more hasn’t been done to secure the currency (even the updates to the currency in the early 2010s were very meh.)