A Clinical Study to Test if an Investigational Treatment Called BNT326 is Safe and Potentially Beneficial When Used Alone or in Combination With Other Investigational Treatments Such as BNT327, for People With Advanced Malignant Tumors

Key Inclusion Criteria (applicable to all participants and all parts unless otherwise specified): * Aged ≥18 years at the time of giving informed consent. Local laws will be followed if the age of consent is older. * Have histologic or cytologic documented advanced disease, either at relapse or upon diagnosis of metastatic disease. This requirement may be considered met when advanced disease derives from unequivocal progression of a previously biopsied site of disease (e.g., progression of residual tumor after concomitant chemo-radiation for Stage III NSCLC). * Have measurable disease defined by RECIST v1.1. * All participants must provide a tumor tissue sample (Formalin-fixed paraffin-embedded \[FFPE\] slides) from archival tissue. The archival tissue can be an FFPE block or freshly cut slides derived from the advanced setting or a new/fresh tumor biopsy. * Have ECOG performance status of 0 or 1. * Have adequate organ and bone marrow function (as specified in the protocol) within 7 days before randomization/enrollment. * Cohort 1A: * Have histologically or cytologically confirmed diagnosis of unresectable or metastatic cutaneous melanoma not amenable to local therapy. * Participants must have previously received a PD-1 or PD-L1 inhibitor, and, for participants with human gene that encodes a protein called B-Raf (BRAF) gene mutant melanoma, a prior treatment regimen that included vemurafenib, dabrafenib, or another BRAF gene inhibitor with or without mitogen-activated p…