Upgrading a ThinkPad T450s with an M.2 SSD - James Ridgway
Restored Lenovo ThinkPad T450 2.3GHz DC i5 4GB 500GB Windows 10 Pro 64 Laptop B Camera (Used) - Walmart.com
laptop - Thinkpad T450s WWAN M.2 slot - M or B key? - Super User
Lenovo ThinkPad T450 i5-5200U 8GB New Drive 240GB SSD 1600x900 A Class Windows 10 Professional NEW 240GB SSD \ Windows 10 Professional | Laptops \ Brand \ Lenovo \ Lenovo ThinkPad | AMSO
Looks like m.2 2280 worked out just fine for t450s : r/thinkpad