Assuming you mean the microwave band at typical power outputs (in the order of millions-watts) then absolutely nothing reproducible. Accordingly, there is no reliable evidence for non-thermal effects of MWR. This isn't surprising; mw photons do not carry near enough energy to ionize. The postulated existence of electromagnetic hyper sensitivity too seems a largely psychosomatic condition with no relationship to mwr. I've written about this for a non expert audience here, with a few papers hyperlinked in text.
The term non-thermal should be used carefully. In the case of mobile phones, since some of these devices emit relatively high intensity EM fields, thermal effects should not be discounted. If the author was referring to "low-intensity effects", a list of low-intensity effects can be found in Levitt and Lai, Environmental Reviews 18:369-395, 2010.
Another important "non-termal" effect of these radiation is produced on the calcium channels:
Pall, M. L. (2013). Electromagnetic fields act via activation of voltage‐gated calcium channels to produce beneficial or adverse effects. Journal of cellular and molecular medicine, 17(8), 958-965.