In order for you to play Shadow of the Tomb Raider on Linux with minimal graphics settings, your computer must meet the following requirements
Operating System:
Ubuntu 18.04 64-bit
Processor (CPU):
3.4GHz Intel Core i3-4130
Memory (RAM):
8 GB RAM
Graphics Card:
2GB AMD R9 285 (GCN 3rd Generation), 2GB Nvidia GTX 680
In order to play Shadow of the Tomb Raider on Linux with maximum graphics settings, you need a computer with a configuration no worse than the following
Operating System:
Ubuntu 18.04 64-bit
Processor (CPU):
3.4GHz Intel Core i7-4770
Memory (RAM):
16 GB RAM
Graphics Card:
8GB AMD Radeon RX 480, 8GB Nvidia GTX 1080
Storage:
40 GB available space