If you wanted to do it manually, you’d probably want to use enumerate() or somehow keep track of the index of each list. Then in a single loop you’d access the same index in each list.
But you have zip() to pull in the corresponding elements from both lists so you don’t have to index it yourself.
ips = ["10.180.0.73", "10.180.0.168"]
names = ["eu-de-1a", "eu-de-1b"]
for ip, name in zip(ips, names):
print(f"{ip}_{name}")