C++ conditionally call functions based on type of the template parameter

Suppose that I have a couple of functions to process different types of arguments. For example processInt for processing int variables and processString for processing std::string variables.

int processInt(int i) 
{
    return i;
}

string processString(string s)
{
    return s;
}

And, I have a template function called foo which takes either of int or std::string as argument. And inside this function I need to conditionally call the processInt or processString based on the variable type sent to it as the argument. The foo function would look like this:

#include <type_traits>

template<typename T>
T foo(T value)
{
    T variable;
    if (std::is_same<T, int>::value) 
    {
        variable = processInt(value); 
    }
    else if (std::is_same<T, string>::value)
    {
        variable = processString(value);
    }
    return variable;
}

int main() {
    string s = "Abc";
    int i = 123;
    cout << foo(s) << " " << foo(i) << endl;     
}

However, with the above foo function I get the following errors:

error: no matching function for call to 'processInt'
                variable = processInt(value); 
                           ^~~~~~~~~~
note: in instantiation of function template specialization 'foo<std::__cxx11::basic_string<char> >' requested here
    cout << foo(s) << " " << foo(i) << endl;    
            ^
note: candidate function not viable: no known conversion from 'std::__cxx11::basic_string<char>' to 'int' for 1st argument
int processInt(int i) 
    ^
error: no matching function for call to 'processString'
                variable = processString(value);
                           ^~~~~~~~~~~~~
note: in instantiation of function template specialization 'foo<int>' requested here
    cout << foo(s) << " " << foo(i) << endl;    
                             ^
note: candidate function not viable: no known conversion from 'int' to 'std::__cxx11::string' (aka 'basic_string<char>') for 1st argument
string processString(string s)
       ^

Source code: https://godbolt.org/z/qro8991ds

How could I do this correctly to conditionally call functions based on type of the template parameter in generic functions?