Markdown is not highlighted

Question

I am unable to turn on syntax highlighting for Markdown. How do I do it?

Here's my version information:

VIM - Vi IMproved 8.2 (2019 Dec 12, compiled May 15 2020 15:48:23)
Included patches: 1-758

Here's the relevant part of my vimrc

" Highlighting for markdown
autocmd BufNewFile,BufFilePre,BufRead *.md set filetype=markdown.pandoc

augroup filetype_markdown
  autocmd FileType markdown onoremap i= :<c-u>execute "normal! ?^==\\+$\r:nohlsearch\rkvg_"<cr>
  autocmd FileType markdown onoremap i- :<c-u>execute "normal! ?^--\\+$\r:nohlsearch\rkvg_"<cr>
augroup END

Originally, I had just the first block above in my vimrc based on this: https://stackoverflow.com/questions/10964681/enabling-markdown-highlighting-in-vim

It wasn't working, so I added the second block based on this: Vim not recognizing markdown and tex files

Answer 1

You need to turn on syntax highlighting explicitly:

syntax enable

Answer 2

Per comment to original post (@D.BenKnoble), I set :syntax enable, and the Markdown highlighting worked. Run :help :syntax for more details. (Scroll to the top of the help page and read down.) Apparently :syntax on has similar but not identical behavior.