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
How to upgrade or add an SSD to Lenovo's Legion 5i 15 | Windows Central
How to upgrade the SSD in your Lenovo Legion Y7000 | Windows Central
Lenovo Legion 5 Pro 16ACH6H Right SSD Replacement - iFixit Repair Guide
Upgrade RAM and add SSD : r/LenovoLegion
Disassembly and upgrade SSD HDD on LENOVO LEGION Y530 m.2, replace, repair, guide, DIY - YouTube