Yes, Legion 5 Pro has two NVMe PCIe 3.0 2280 SSD slots, the second slot is empty and has a pre-installed heatsink with a thermal pad. (I installed Samsung 970 Evo 1TB
Lenovo Legion 7i - Upgrading the Storage - YouTube
Best Buy: Lenovo Legion Tower 5i Gaming Desktop Intel Core i7-11700 16GB Memory NVIDIA GeForce GTX 1660 Super 256GB SSD + 1TB HDD Raven Black 90RS0003US