Vitux published a tutorial about installing CMake on Ubuntu 20.04 LTS.

How to Install CMake on Ubuntu 20.04 LTS

CMake is an open-source, cross-platform family of tools designed to build, test, and package software. CMake is used to control the software compilation process using simple platform and compiler-independent configuration files, and generate native makefiles and workspaces that can be used in the compiler environment of your choice. The suite of CMake tools was created by Kitware in response to the need for a powerful, cross-platform build environment for open-source projects such as ITK and VTK.

How to Install CMake on Ubuntu 20.04 LTS