Depends. Sepsis is your body's generalized inflammatory response to an infection somewhere. What organ systems are affected depend a bit on your medical conditions and depend a lot on where the infection starts. For instance, pneumonia that leads to sepsis will definitely affect your lungs first. In general, the organ systems most commonly affected by sepsis are your kidneys, your lungs, and your heart.
Varies. Sepsis is not itself an infection - but the bodies response to a severe infection +/- any toxins produced by that infection. The organs most likely to be affected vary by the type of infection and patient characteristics. Typically the cardiovascular system will be stressed and (depending on if it begins to fail or not) other organs are affected downstream from this. Pulmonary, renal, skin, . .