Although CCS2 is essentially the only relevant standard in Europe today, many manufacturers selling equipment internationally — or serving fleets with imported vehicles — also need to understand CCS1 and CHAdeMO.
CCS1 is the North American and South Korean variant of the Combined Charging System: it shares the same philosophy as CCS2 (a single connector for both AC and DC), but with a different pin layout designed for the single-phase electrical grids typical of those markets.
CHAdeMO is an older, Japanese-origin standard that uses a completely different connector dedicated exclusively to DC charging, without combining AC in the same connector. It was a pioneer in fast charging, but has been losing ground to CCS as more automakers align with the combined standard.
For anyone operating in Europe, the practical takeaway is simple: CCS2 is the default choice and, in most cases, the only one required by regulation. Knowing CCS1 and CHAdeMO is mainly useful if your fleet includes vehicles imported from other markets or if you work with international clients.