The OO interface to CGI.pm is largely pointless. You never need more that one object in your programs. I would always use the function interface instead.

use CGI ':cgi';

# And later...

my $foo = param('foo');

Also, please consider not using CGI at all. It's the 21st century - we have far better tools. Plesse take a look at

https://metacpan.org/pod/CGI::Alternatives

for Perl-based alternatives.