If you are compiling CMS AN, Papers or PhD thesis with centrally proivided TDR scripts you will often find that packages are missing and your latex document is not compiled as you wanted to. For example these packages are not included
\usepackage{makecell}
\usepackage{booktabs,siunitx}
\usepackage{array,enumitem,booktabs,adjustbox}
\usepackage{units}
\usepackage{slashed,amsfonts,mathrsfs,bbm,bbding,pifont, fontawesome}
If you are sure you have them on your installed TeX distribution then it is not enough to declare \usepackage in you main .tex file (e.g. AN-2020-bla.tex) as it will be totally ignored.
To add packages from your TeX distribution you should add the \usepackage declaration in one of the following files depending on which type of document you are trying to compile:
utils/general/cms-tdr.cls
utils/general/cms-tdr-note.cls
utils/general/cms-tdr-atlas.cls
If you open one of them you will see multiple \usepackage declarations and you can add yours.