The purpose of this first-in-human study is to find out if BNT314 is safe when it is used alone in patients with different types of cancer. This is a dose escalation study in which patients will be assigned to multiple dose levels (DLs) of BNT314 given alone. By escalating the dose with a small group of patients, the Maximum Tolerated Dose which is the highest dose with acceptable safety and manageable side effects, or the maximum administered dose will be investigated.