This study will be conducted in two stages (phase Ib and phase II). Phase Ib: To explore the safety and tolerability of Docetaxel for Injection (Albumin-bound) (75 mg/m^2 and 100 mg/m^2) combined with Nivolumab 360 mg. Dose exploration will be started at low dose and proceed in turn.~Phase II: According to the recommended phase II dose (RP2D) determined in the phase Ib study, a phase II study of Docetaxel for Injection (Albumin-bound) combined with Nivolumab will be conducted to observe the efficacy of the combination regimen, with ORR as the primary study endpoint. Simon's optimal 2-stage design will be adopted for phase II study.~All patients in Phase Ib and Phase II will be treated with Docetaxel for Injection (Albumin-bound) combined with Nivolumab until participants meet the criteria for termination or withdrawal criteria, for a maximum of 2 years
This trial is a single-arm, multicenter phase Ib/II clinical study to evaluate the efficacy and safety of Docetaxel for Injection (Albumin-bound) combined with Nivolumab and the pharmacokinetic characteristics of Docetaxel in patients with recurrent or metastatic SCCHN who are positive for PD-L1 expression and have progressed on or after platinum-based therapy.