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Lenovo's specs say that it should be compatible.
System has one HDD slot or one M.2 2280 slot exclusively for storage
Some: HDD / SATA 6.0Gb/s, 2.5" wide, 7mm high, Active Protection System
Some: SSD / SATA 6.0Gb/s, 2.5" wide, 7mm high (e.g. xxxGB SSD)
Some: M.2 SSD / PCIe NVMe, PCIe 3.0 x 2, 16Gb/s
Some: 128GB M.2 SSD / PCIe NVMe, PCIe 3.0 x 2, 16Gb/s, in WWAN slot as 2nd Storage, mutually exclusive with WWAN
Lenovo's 128GB maximum reflects the largest size they tested when the model was introduced. There should be no reason why a larger drive won't work.
However see this Reddit discussion and especially the table at the end. The T480 and L480 are the same generation so the information should apply,
My comments are mine. I don't work for or speak for Lenovo.
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