Type Ia supernovae (SNe Ia) are thought to be white dwarf stars composed primarily of carbon and oxygen which undergo explosive nuclear burning. SNe Ia are important across many astrophysical domains, serving as standardizable candles for cosmology, sources of cosmic rays, turbulence, and enriched isotopes for the interstellar medium, and endpoints of binary evolution. An isolated white dwarf is inherently stable. Therefore, virtually all explanations for the SN Ia explosion invoke accretion from (or collision with) a companion star. However, the nature of the companion star and the explosion mechanism has remained unclear. The most frequently discussed possibilities are the explosion of a near-Chandrasekhar mass white dwarf accreting from a non-degenerate companion in the single-degenerate channel, or another white dwarf in the double-degenerate channel. I will discuss how a consensus picture for the outcome of these two channels is slowly beginning to emerge, based upon decades of effort from observers and theorists. A new generation of observations from JWST, Nancy Roman, and XRISM will test this picture, both in the observations of UVOIR SNe Ia transients and in the X-ray in their galactic remnants. Those unable to attend the colloquium in person are invited to participate online through Zoom (Meeting ID: 942 0262 2849, passcode 792771) using the link: https://eu02web.zoom-x.de/j/94202622849?pwd=dGlPQXBiUytzY1M2UE5oUDRhbzNOZz09