A Study to Investigate Safety and Tolerability of TransCon IL-2 β/γ Alone or in Combination With Pembrolizumab and/or TransCon TLR7/8 Agonist or Other Anticancer Therapies in Adult Participants With Locally Advanced or Metastatic Solid Tumor Malignancies

Key Inclusion Criteria:

• At least 18 years of age, or country defined local legal age

• Demonstrated adequate organ function at screening

• Life expectancy >12 weeks as determined by the Investigator

• Female and male participants of childbearing potential who are sexually active mustagree to use highly effective methods of contraception

• Participants must have histologically confirmed locally advanced, recurrent, ormetastatic solid tumor malignancies that cannot be treated with curative intent (surgery or radiotherapy), with the exception of the neoadjuvant cohorts

• Part 1 and Part 2: Eastern Cooperative Oncology Group (ECOG) performance status 0, 1, or 2

• Part 3 and Part 4: Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1

• Participants who have undergone treatment with anti-PD-1, anti-PD-L1, oranti-cytotoxic T-lymphocyte-associated protein (CTLA-4) antibody must have a washoutof at least 4 weeks from the last dose and evidence of disease progression perinvestigator assessment before Cycle 1 Day 1 (C1D1) with the exception of theneoadjuvant cohorts

• Participants who have previously received an immunotherapy prior to C1D1 must haveany immune-related toxicities resolved to ≤Grade 1 or baseline (prior to theimmunotherapy) to be eligible, with the exception of participants on well controlledphysiologic endocrine replacement

• Part 3: Neoadjuvant cohorts: participants must have completely resectable disease

Key Exclusion Criteria:

• Symptomatic central nervous system metastases and/or carcinomatous meningitis

• Active autoimmune diseases, regardless of need for immunosuppressive treatment, withthe exception of participants well controlled on physiologic endocrine replacement

• Any uncontrolled bacterial, fungal, viral, or other infection

• Significant cardiac disease

• A marked clinically significant baseline prolongation of QT/QTc interval (e.g.,repeated demonstration of a QTc interval >480 ms) [CTCAE Grade 1]) usingFridericia's QT correction formula

• Positive for human immunodeficiency virus (HIV) or has known active hepatitis B or Cinfection

• Known hypersensitivity to any study treatment(s) used in the specific studypart/cohort

• Participants who have been previously treated with IL-2 or IL-2 variants (allparticipants)

• Systemic immunosuppressive treatment with the exception for patients oncorticosteroid taper (for example, for chronic obstructive pulmonary diseaseexacerbation).

• Vaccination with live, attenuated vaccines within 4 weeks of C1D1

• Treatment with any other anti-cancer systemic treatment (approved orinvestigational) or radiation therapy within 4 weeks of C1D1

• Part 3: Other active malignancies within the last 2 years

• Women who are breastfeeding or have a positive serum pregnancy test during screening