This study is testing a new drug called CFT7455 for people with certain blood cancers: Non-Hodgkin's Lymphoma (NHL) and Multiple Myeloma (MM). The study will see how safe and effective the drug is. CFT7455 will be given by mouth, and for those with MM, it may also be combined with another medicine called dexamethasone. To be part of the study, you need to be at least 18 years old, have certain types of NHL or MM that have come back or not responded to treatment, and meet other health criteria.

**Key Points:**

• The study requires you to visit the hospital or clinic for check-ups.
• Participants must not have certain health conditions or recent treatments that could interfere with the study.
• There are specific rules about contraception and pregnancy during the study.