Inclusion Criteria:

• Are 18 years of age or older.
• Have histologic evidence of locally or regionally advanced or stage IV malignancy.
• Are considered appropriate for starting therapy with anti-PD-1/anti-PD-L1 monoclonal antibody by their treating physician (prior therapy with ICI is allowed).
• Have an understanding of the protocol and its requirements, risks, and discomforts.
• Are willing to undergo peripheral blood collection at the time points mentioned in the protocol.
• Are able and willing to sign an informed consent.

Exclusion Criteria:

• Patients under 18 years of age.
• Inability of the patient to understand the informed consent or be compliant with the protocol.
• Patients receiving any concurrent anti-cancer therapy or investigational agents (with the exception of an anti-PD-1/anti-PD-L1 agent as mentioned above).
• Patients who are pregnant, nursing, or are of childbearing potential and are unwilling to employ adequate contraception.