The purpose of this study is to evaluate the pharmacokinetic similarity, safety, and immunogenicity of Envafolimab in healthy male subjects before and after the manufacturing process change.

Inclusion Criteria:

1. Be able to fully read, understand, and sign the informed consent form;
2. Male subjects aged 18-45 years
3. Clinical examinations in the screening period are normal or abnormal without clinical significance;
4. A body mass index (BMI) in the range of 19 to 26 kg/m22, and a body weight between 50 and 85 kg;
5. Use effective contraceptive methods from the beginning of the informed consent to 5 months after the use of the drug, and have no plans to give birth or donate sperm.

Exclusion Criteria:

1. Systolic blood pressure ≥140 mmHg/ diastolic blood pressure ≥90 mmHg or systolic blood pressure < 90 mmHg/ diastolic blood pressure < 60 mmHg, pulse > 100 beats /min or < 50 beats /min at screening or baseline examination;
2. QT interval (QTcF) ≥450;
3. Estimated glomerular filtration rate eGFR < 90 ml/min/1.73m2;
4. Thyroid function beyond the normal range;
5. ALT > ULN Or AST > ULN;
6. Prior treatment with a PD-1/L1 inhibitor;
7. Have taken any prescription drug, over-the-counter drug, any vitamin product or herbal or health product within 14 days prior to study drug administration;
8. Had a history of upper respiratory tract infection or other acute infection within 14 days prior to study drug administration;
9. Positive hepatitis B surface antigen, hepatitis C antibody, or human immunodeficiency virus antibody or syphilis.