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 5 Pro Disassembly (RAM, M.2 SSD upgrade options)
Amazon.com: Lenovo Legion 5 15.6" Full HD IPS 165Hz Gaming Laptop (8-Core Ryzen 7-5800H, 64GB RAM, 2TB PCIe SSD, GeForce RTX 3050 Ti 4GB) RGB Backlit, 3D Nahimic Audio, w/HDMI Cable, Windows
Lenovo Legion 5 Pro 16ACH6H Left SSD Replacement - iFixit Repair Guide
How to upgrade or add an SSD to Lenovo's Legion 5i 15 | Windows Central