Sequential Toripalimab and Paclitaxel in Patients With Head and Neck Squamous Cell Cancer (HNSCC) and Poor Performance Status

Inclusion Criteria: * Participants must have histologically confirmed HNSCC deemed to be metastatic or incurable by the treating physician. Participants can have incurable disease at presentation or have been treated with definitive curable surgical resection, chemoradiotherapy (CRT), or both, then relapsed with non-curable disease. Participants diagnosed with HNSCC stage IV-C or metastatic/non-resectable, relapsed disease are eligible for this study * Participant must have measurable disease, defined by RECIST v1.1. * Participant must be able to understand a written informed consent document and be willing to sign it. * Participants must be 18 years of age or older. * Participant must have a life expectancy of at least six months. * Participant must have an ECOG performance score of 2. * Participant must have: 1. Total bilirubin ≤ 3 times upper limit of normal (ULN) 2. Hemoglobin \> 8 g/dL. Transfusion is permitted 3. Absolute neutrophil count (ANC) \> 1.0 K/mm3. Granulocyte colony-stimulating factor (G-CSF) is NOT permitted * Paclitaxel has known embryo- and fetotoxic effects. Therefore, women of childbearing potential must agree to avoid becoming pregnant and male participants should avoid impregnating a female partner and donating sperm starting at initiation of treatment up until at least 30 days after last dose of toripalimab or paclitaxel. Exclusion Criteria: * Participants with known untreated brain metastases will be excluded from this clinical trial. Stable brain metastases will be allowed, and it will be confirmed by stable brain MRI with and without contrast within 8 weeks of signing consent. * Participants with uncontrolled chronic obstructive pulmonary disease (COPD), heart disease, or autoimmune disease, in the opinion of the treating physician. * Participants who are taking any other investigational drugs. * Participants who are taking prednisone or equivalent steroid \>10 mg per day prior to the start of treatment. * The washout period is at the treating physician's discretion. * Once participants are on study, they may be treated with steroids and other immunosuppressants per standard of care. * Participants with a history of allergic reactions attributed to toripalimab, paclitaxel, or medicines containing Kolliphor ELP (Polyoxyl 35 Castor Oil, NF). * Participants who are pregnant or breastfeeding. If a breastfeeding participant would like to be part of this study, breastfeeding must be discontinued. * Participants who have end-stage renal failure are eligible for this study unless they have had a kidney transplant. * Participants that do not agree to be followed according to the study protocol or have cognitive or physical inability to follow the treatment plan.