This plugin has all functionality of OMZ cpanm completion but it also allows cpan install word<tab> and cpanm install <tab> to complete remote CPAN package from output of perl -MCPAN -e 'CPAN::Shell->m("/$package/")'. The word before tab completion must be >= 2 characters in length to reduce crashing of zsh from too many packages. ZPWR_CPAN_MIN_PREFIX controls the min length of prefix.

~/.zshrc

source "$HOME/.zinit/bin/zinit.zsh"
zinit ice lucid nocompile
zinit load MenkeTechnologies/zsh-cpan-completion

cd "$HOME/.oh-my-zsh/custom/plugins"  && git clone https://github.com/MenkeTechnologies/zsh-cpan-completion.git

Add zsh-cpan-completion to plugins array in ~/.zshrc

git clone https://github.com/MenkeTechnologies/zsh-cpan-completion.git

source zsh-cpan-completion.plugin.zsh or add code to zshrc or any startup script