An eSIM is a virtual SIM built into a device. Instead of a removable card, the identity lives in a chip with its own unique identifier — the EID. As more laptops ship with built-in mobile (WWAN) modules, the eSIM becomes one more thing that can identify a device.
What the EID is
The EID is a long number burned into the eSIM chip, much like an IMEI on a phone. It is stable, unique, and visible to the mobile carrier.
Does it matter for HWID today?
For now, game anti-cheats and most software do not read eSIM identifiers — the established hardware fingerprint is built from the motherboard, disks, network adapters and CPU. The eSIM is more of a forward-looking concern: as laptops with WWAN modules become common, it is a plausible future fingerprinting signal.
What you can do
The EID lives in the eSIM's own firmware, so software HWID tools do not change it. If you have a laptop with a WWAN module and you are concerned about this layer, the simplest option is to disable the WWAN / mobile-broadband device in your BIOS or Device Manager — that removes the signal entirely.