Short-term Fasting Prior to PD-1/PD-L1 Inhibitor Therapy for of Advanced or Metastatic Skin Malignancy

Inclusion Criteria:

* Histologically confirmed solid tumor malignancy for which PD-1/PDL1 inhibition based immunotherapy is recommended as standard of care therapy, as monotherapy or in combination with other checkpoint inhibitors. Acceptable PD-1/PD-L1 inhibitors include\*:
* Pembrolizumab
* Nivolumab
* Cemiplimab
* Dostarlimab
* Retifanlimab
* Toripalimab
* Tislelizumab
* Atezolizumab
* Avelumab
* Durvalumab \* Additional PD-1/PD-L1 inhibitors may be considered, with the approval of the principal investigator (PI), and will require a future amendment to the protocol

Other immune checkpoint inhibitors (such as those targeting CTLA-4, LAG-3, etc) that may be used in combination with PD-1/PD-L1 inhibitors as standard of care therapy include\*\*:

* Ipilimumab
* Tremelimumab
* Relatlimab

  \*\*Additional checkpoint inhibitors may be considered, with the approval of the PI, and will require a future amendment to the protocol.
* Advanced or metastatic cutaneous tumor with measurable disease evaluable by RECIST criteria. Patients with other solid tumors may be eligible if they have a cutaneous metastasis amenable to biopsy (with approval of PI only)
* No more than 2 lines of prior systemic therapy (not including neoadjuvant or adjuvant therapy)
* Eastern Cooperative Oncology Group (ECOG) performance status 0-1
* Absolute neutrophil count \>= 1,000/mcL
* Absolute lymphocyte count \>= 500/mcL
* Hemoglobin \>= 8.0 g/dL
* Platelets \>= 75,000/mcl
* Total bilirubin =\< 1.5 x institutional upper limit of normal
* Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase \[SGPT\]) =\< 3 x institutional upper limit of normal
* Creatinine =\< 1.8 mg/dl or calculated creatinine clearance \> 40 ml/min
* Women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry, for the duration of study participation, and for 90 days following completion of therapy. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately
* A female of child-bearing potential is any woman (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria:

  * Has not undergone a hysterectomy or bilateral oophorectomy; or
  * Has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months)
* Body mass index (BMI) \>= 18.5
* Ability to understand and the willingness to sign a written informed consent and comply with short-term fasting during study and other study-related procedures

Exclusion Criteria:

* Patients with history of diabetes mellitus are not eligible for this study

  * Note: patients with pre-diabetes or a history of diabetes which subsequently resolves, who are not taking metformin or any other diabetes medications are eligible
* Patients with recent significant or unexplained weight loss that the investigator feels may pose an unacceptable risk for enrollment should be excluded. (Candidates who are overweight and have intentionally lost weight via diet or exercise should be excluded, for instance)
* Subjects on medications that may not be safely stopped during the fasting portion of the study, or which may not be safely consumed without food
* Prior history of syncope with caloric restriction in the past or other medical comorbidity which would make fasting potentially dangerous
* Prior treatment with any agent that blocks the PD-1 or PD-L1 pathway
* Prior treatment with other immune modulating agents within fewer than 4 weeks, prior to the first dose of PD-1/PD-L1 inhibition. Examples of immune modulating agents include blockers of CTLA-4, 4-1BB, OX-40, therapeutic vaccines, or cytokine therapies
* Patients must not be receiving other concomitant biologic therapy, hormonal therapy, chemotherapy, other anti-cancer therapy or any other investigational agents while on this protocol
* Radiation therapy, non-cytotoxic agents or investigational agents in the 4 weeks prior to the first dose of PD-1/PD-L1 inhibition
* Immunosuppressive systemic corticosteroids equivalent to prednisone 10 mg or greater in the 14 days prior to the first dose of PD-1/PD-L1 inhibition
* Any major surgery within 14 days prior to the first dose of PD-1/PD-L1 inhibition. Patients must have recovered from any major complications before registration
* Active autoimmune disease requiring systemic treatment in the past 2 years (i.e. use of disease modifying agents or immunosuppressive drugs). Replacement therapy (e.g. thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency, etc) is not considered a form of systemic treatment
* Patients with known brain metastases should be excluded from this clinical trial because of their poor prognosis and because they often develop progressive neurologic dysfunction that would confound the evaluation of neurologic and other adverse events
* History of allergic reactions attributed to compounds of similar chemical or biologic composition to PD-1 or PD-L1 inhibitor
* Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements
* Positive pregnancy test, active pregnancy or nursing/breast-feeding, due to the potential for congenital abnormalities and the potential of this regimen to harm nursing infants
* History of solid organ or bone marrow transplantation