Measurements of the cosmic microwave background (CMB) contain the imprint of both early and late universe physics as well as a variety of millimeter-wavelength astrophysical sources. CMB measurements are a cornerstone of our now exceptionally precise Lambda-CDM model of cosmology, however, many questions remain. Did an inflationary epoch occur a fraction of a second after the Big Bang? What is the nature of dark energy? Is the Hubble constant controversy new physics or simply measurement systematics? 

I will describe the SPT-3G receiver that is currently installed on the South Pole Telescope and how it observes the CMB in search of answers. Now starting the fifth year of survey observations, SPT-3G data is already providing tantalizing hints about what scientific goalposts will be possible in the very near future. I’ll highlight a few of these results as well as providing perspectives on the upcoming CMB-S4 experiment.