Over the last few decades, we have learned a lot about the Universe in its infancy through dedicated observations of the cosmic microwave background (CMB). Upcoming surveys will give us new information about the evolution of structures between us and the CMB through nearly all of cosmic history. I will focus on two methods, namely gravitational lensing and various flavors of the Sunyaev-Zel'dovich effect, highlighting some of the opportunities and challenges. Specifically, and time-permitting, I will discuss (a) a new method to measure the gravitational lensing of the CMB on small scales; (b) constraints on the evolution of matter using correlations between CMB lensing and the lensing of optical galaxies; and (c) the impact of extragalactic foreground emission on the CMB.
