This study is researching an investigational drug called REGN7075 by itself and in combination with cemiplimab with or without chemotherapy. The study is focused on patients with certain solid tumors that are in an advanced stage. The aim of the study is to see how safe and tolerable REGN7075 is by itself and in combination with cemiplimab (with or without chemotherapy), and to find out what is the best dose of REGN7075 to be given to patients with advanced solid tumors when combined with cemiplimab (with or without chemotherapy). Another aim of the study is to see how effective REGN7075 by itself, or in combination with cemiplimab (with or without chemotherapy), is at treating cancer patients.

The study is also looking at:

* Side effects that may be experienced by people taking REGN7075 by itself and in combination with cemiplimab with or without chemotherapy
* How REGN7075 works in the body by itself and in combination with cemiplimab with or without chemotherapy
* How much REGN7075 is present in the blood when given by itself and in combination with cemiplimab with or without chemotherapy
* To see if REGN7075 by itself and in combination with cemiplimab with or without chemotherapy works to treat cancer by controlling the proliferation of tumor cells to shrink the tumor

This phase II trial studies the effect of pembrolizumab alone compared to the usual approach (chemotherapy \[cisplatin and carboplatin\] plus radiation therapy) after surgery in treating patients with head and neck squamous cell carcinoma that has come back (recurrent) or patients with a second head and neck cancer that is not from metastasis (primary). Radiation therapy uses high energy radiation or protons to kill tumor cells and shrink tumors. Cisplatin is in a class of medications known as platinum-containing compounds. It works by killing, stopping or slowing the growth of cancer cells. Carboplatin is also in a class of medications known as platinum-containing compounds. It works in a way similar to the anticancer drug cisplatin, but may be better tolerated than cisplatin. Carboplatin works by killing, stopping or slowing the growth of cancer cells. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer and may interfere with the ability of tumor cells to grow and spread. Giving pembrolizumab alone after surgery may work better than the usual approach in shrinking recurrent or primary head and neck squamous cell carcinoma.

This phase II/III trial studies how well sentinel lymph node biopsy works and compares sentinel lymph node biopsy surgery to standard neck dissection as part of the treatment for early-stage oral cavity cancer. Sentinel lymph node biopsy surgery is a procedure that removes a smaller number of lymph nodes from your neck because it uses an imaging agent to see which lymph nodes are most likely to have cancer. Standard neck dissection, such as elective neck dissection, removes many of the lymph nodes in your neck. Using sentinel lymph node biopsy surgery may work better in treating patients with early-stage oral cavity cancer compared to standard elective neck dissection.

Ficerafusp alfa is directed against two targets, Epidermal Growth Factor Receptor (EGFR) and Transforming Growth Factor beta (TGF-).

This study intends to evaluate the safety and efficacy of ficerafusp alfa in combination with pembrolizumab versus placebo with pembrolizumab in 1L PD-L1-positive, recurrent or metastatic Head and Neck Squamous Cell Carcinoma (HNSCC).

This phase II trial compares the effect of usual treatment of docetaxel chemotherapy plus trastuzumab, to ado-emtansine (T-DM1) in patients with HER2-postive salivary gland cancer that has come back (recurrent), that has spread from where it first started (primary site) to other places in the body, or cannot be removed by surgery (unresectable). This trial is also testing how well trastuzumab deruxtecan works in treating patients with HER2-low recurrent or metastatic salivary gland cancer. Trastuzumab is a form of targeted therapy because it works by attaching itself to specific molecules (receptors) on the surface of cancer cells, known as HER2 receptors. When trastuzumab attaches to HER2 receptors, the signals that tell the cells to grow are blocked and the cancer cell may be marked for destruction by body's immune system. Trastuzumab emtansine contains trastuzumab, linked to a chemotherapy drug called emtansine. Trastuzumab attaches to HER2 positive cancer cells in a targeted way and delivers emtansine to kill them. Trastuzumab deruxtecan is a monoclonal antibody called traztuzumab, linked to a chemotherapy drug called deruxtecan. Trastuzumab is a form of targeted therapy because it attaches to specific molecules (receptors) on the surface of cancer cells, known as HER2 receptors and delivers deruxtecan to kill them. Docetaxel is in a class of medications called taxanes. It stops cancer cells from growing and dividing and may kill them. Trastuzumab emtansine may work better compared to usual treatment of chemotherapy with docetaxel and trastuzumab or trastuzumab deruxtecan in treating patients with recurrent, metastatic or unresectable salivary gland cancer.

The goal of this phase I clinical trial is to evaluate the usefulness of an imaging test (zirconium Zr89 panitumumab \[89Zr panitumumab\]) with positron emission tomography (PET)/computed tomography (CT) for diagnosing the spread of disease from where it first started (primary site) to other places in the body (metastasis) in patients with head and neck squamous cell carcinoma. Traditional PET/CT has a low positive predictive value for diagnosing metastatic disease in head and neck cancer. 89Zr panitumumab is an investigational imaging agent that contains radiolabeled anti-EGFR antibody which is overexpressed in head and neck cancer. The main question this study aims to answer is the sensitivity and specificity of 89Zr panitumumab for the detection of indeterminate metastatic lesions in head and neck cancer.

Participants will receive 89Zr panitumumab infusion and undergo 89Zr panitumumab PET/CT 1 to 5 days after infusion. Participants will otherwise receive standard of care evaluation and treatment for their indeterminate lesions.

Researchers will compare the 89Zr panitumumab to standard of care imaging modalities (magnetic resonance imaging (MRI), CT, and/or PET/CT).