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
DIY - replace hdd on ssd Lenovo Legion Y520-15 and Upgrade ram DDR4 to 8GB or 16GB,DIY tourtial - YouTube