This study is looking at a drug called CFT7455 to check how safe and tolerable it is for people with certain types of blood cancers, **Non-Hodgkin's Lymphoma** (NHL) and **Multiple Myeloma** (MM). These are conditions where the body's cells grow uncontrollably. This study is for people whose cancer hasn't responded to usual treatments. They will take CFT7455 by mouth, sometimes with another drug called dexamethasone, to see if it helps. The study will look at how the body absorbs and reacts to the drug and its effects on cancer.

• The study involves taking an oral medication, possibly with another drug for MM patients.
• Participants must have certain types of blood cancer that have not responded to prior treatments.
• The study requires agreeing to specific health tests and not being pregnant or breastfeeding.