Cgroups aka control groups is a Linux kernel feature for limiting, measuring, and controlling resource usage by processes. Cgroups however is not a command, but rather a collection of commands, see the relevant pages below. More information: https://www.kernel.org/doc/Documentation/cgroup-v2.txt.
cgclassify:tldr cgclassify
cgcreate:tldr cgcreate
cgexec:tldr cgexec