File Descriptor Limit
Linux kernel has fairly low default limit of file descriptors that a given process can open - only 4096. Games can use a lot of them for inter-process communication, synchronization primitives and reading assets.
Setting this limit higher is necessary to be able to run a lot of the games out there.
Systemd-based Linux Distributions
Systemd 240 or newer by default sets the soft limit to 1024 and hard limit to 524288. No action is necessary.
If you want to further alter those values see DefaultLimitNOFILE in man systemd.conf.d.
Non-Systemd Linux Distributions With PAM
If your distribution is using PAM and has pam_limits.so enabled you can configure the limits via limits.conf, e.g /etc/security/limits.conf.
* hard nofile 524288
Everything Else
Please consult documentation of your distributions.