Additional Study Information: The purpose of this research is to learn about what effects, both good and/or bad, an experimental drug called TransCon IL-2 / has when given by itself or in combination with pembrolizumab, SOC chemotherapy, or TransCon TLR7/8 Agonist, or in combination with pembrolizumab and SOC chemotherapy. TransCon IL-2 / works by blocking the reproduction and spread of cancer cells. The study drugs, TransCon TLR7/8 Agonist and TransCon IL-2 /, have not been approved to be used by the Food and Drug Administration FDA for this study population. TransCon IL-2 / and TransCon TLR7/8 Agonist whereas designed to stimulate your immune system to fight your cancer. We also want to find a dose of TransCon IL-2 / and TransCon TLR7/8 Agonist that is safe and tolerable for adult patients who have advanced cancers, whose cancer came back after standard treatment, or whose disease has not responded to standard cancer treatment. We are also trying to decide on the best dose that patients can take safely for use in future studies. There are three parts to this study, two dose escalation portions (Parts 1 and 2) and a dose expansion portion (Part 3). CUIMC will only be partaking in Part 3. The part you are enrolled in depends on the type of cancer you have and the status of your disease; it may also depend on past treatment(s) for your cancer. This is a first in human study, which means a new drug or treatment is tested in humans for the first time.