I have the XDS 3.3 in 9 and the PPS M1 in 40. To my surprise, an Aholster kydex pocket holster for my XDS works better than expected for the PPS M1. It fits, just a tiny bit looser than the XDS but it does fit. I have a kydex IWB for the XDS from stay holstered. It fits the XDS perfect but not the PPS M1. It's very nicely formed to the XDS, and the PPS M1 trigger guard is too wide to fit.
I have an IHL leather holster (Trojan) boned for the PPS M1, and the XDS would not be a good match - its just a little too thick and I wouldn't try it for fear of ruining the fit.
Non-boned leather might work for both though, something that is not specifically made for one gun only, something in leather that has a bit more give.