PRIMARY OBJECTIVE: I. To evaluate safety and feasibility of a single intramuscular injection of efineptakin alfa (NT-I7) in patients with locally recurrent squamous cell carcinoma of head and neck (SCCHN). SECONDARY OBJECTIVES: I. To describe changes in absolute lymphocyte count (ALC) in peripheral blood after a single dose of NT-I7. II. To describe changes in tumor infiltrating lymphocytes (TIL) in tumor microenvironment of surgical specimen after a single dose of NT-I7. III. To evaluate changes in immune subsets in peripheral blood after a single dose of NT-I7 and after surgery. EXPLORATORY OBJECTIVE: I. To make assessment of exploratory biomarkers for pharmacodynamic activity of NT-I7 in peripheral blood, and/or tumor tissue. OUTLINE: Patients receive one dose of efineptakin alfa intramuscularly (IM). After completion of study treatment, patients are followed up for 35 days after dose or 21 days after surgery.