If I cancel iCloud subscription at any point in time, does it mean I will loose all my photos and files?
what happens to my iCloud files if I cancel my subscription
Question marked as
Yes, unless you take action. Whatever content that you have that exceeds the 5GB of free storage that you get from Apple will be lost within 30 days of cancelling unless you archive/save the content that is in iCloud. You will have to download it to a computer or keep it on your device if you don’t want to lose it.
See this for more information.
Archive or make copies of the information you store in iCloud - Apple Support