my @a = 1 .. 4; my @b = "a" .. "d";
my @c = (@a, @b);

# You could even do this - no need to create a new variable:
@a = (@a, @b);

# Or...
push @a, @b;

##</code><code>##

my @c;
push @c, [ $a[$_], $b[$_] ] for 0 .. $#a;