Solid Tumor in Advanced Stage

The trial will test if the combination of bexmarilimab and nivolumab can help patients whose cancers have stopped responding to immunotherapy treatment. It will focus on two cancers: non-small cell lung cancer and melanoma. Early research suggests bexmarilimab may change some immune cells inside the tumour so they create a stronger "attack" signal, which could help other immune cells recognise and kill cancer cells more effectively. This may make it easier for PD-1 immunotherapy drugs to work again by helping the immune system stay active against the tumour. This is a Phase I/II clinical trial. In Phase I, researchers will give increasing doses of bexmarilimab together with a standard (fixed) dose of nivolumab to patients with solid tumours, to find the safest and most suitable dose to use going forward (the recommended Phase 2 dose). In Phase II, the study will treat two groups of patients-one with non-small cell lung cancer and one with melanoma-using that selected dose.

The goal of this clinical trial is to evaluate the safety and tolerability of AD1208 to determine the maximum tolerated dose(MTD) or maximumly administered dose(MAD) in any progressive, locally advanced (unresectable) or metastatic solid tumors. The main questions it aims to answer are: * Which dosage of AD1208 is safe and tolerable for participants? * What medical problems do participants have when taking AD1208? Participants will: * Take drug AD1208 every day up to 1 cycle at the least. * Visit the site once every 1 weeks for checkups and tests during cycle 1 and every 3 weeks from cycle 2 onwards. * Keep a diary of any adverse events and administrated drug