Replaced battery . Trackpad works but keyboard won’t respond .

In principle nothing should go wrong with the keyboard when replacing the battery, since there’s no real overlapping of parts, so if any problem showed up just after replacement it’s probably job related. I’d suggest to get some magnification and a good light source and check that keyboard connector and cable have not suffered any tear during battery replacement and retry connecting them in place. Other than that, something might have been damaged by mistake on the logic board. Removing such tightly glued battery from the topcase needs some force and chemicals, plenty of room for mistakes.