The ThinkPad T490s is a slimmer and lighter version of the T490, and though the RAM is soldered to the board, there is an M.2 PCIe NVMe solid-state drive (SSD) that can be upgraded after purchase. Whether you saved some money at checkout by going with a smaller drive or you want as much speed as possible, here's the hardware you need and how to perform the upgrade.
Full story from the WindowsCentral blog...