Please select the eligibility criteria that correspond to the clinical trial below.
Title: A Phase II Randomized Study of Adjuvant Versus NeoAdjuvant Pembrolizumab (MK-3475) for Clinically Detectable Stage III-IV High-Risk Melanoma
Brief Summary: This phase II trial studies how pembrolizumab works before and after surgery in treating patients with stage III-IV high-risk melanoma. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Giving pembrolizumab before and after surgery may work better compared to after surgery alone in treating melanoma.


Options:
A: Inclusion Criteria:

1. Signed ICF
2. Age ≥ 18 years
3. Histologically confirmed Stage IV (metastatic) or unresectable Stage IIIC (locally advanced) melanoma, as defined by the AJCC, 7th revised edition

   1. Naïve to prior systemic anti-cancer therapy for melanoma, with the following exceptions: Adjuvant treatment with IFN, IL-2, or vaccine therapies, if discontinued at least 28 days prior to initiation of study treatment
   2. Adjuvant treatment with herbal therapies, if discontinued at least 7 days prior to initiation of study treatment
4. Documentation of BRAFV600 mutation-positive status in melanoma tumor tissue (archival or newly obtained) through use of a clinical mutation test approved by the local health authority
5. ECOG of 0 or 1
6. Decision of eligibility for neoadjuvant combined vem+cobi+atezo treatment by in-terdisciplinary tumor board. Patient with limited numbers of metastases and few organ systems involved should be selected, making surgical resection after neo-adjuvant treatment probable.
7. Measurable disease by RECIST V1.1 criteria (must be outside the CNS)
8. Adequate hematologic and end-organ function, defined by the following laboratory test results, obtained within 14 days prior to initiation of study treatment, with the exception of amylase, lipase, and LDH where up to 28 days is acceptable

   * ANC ≥ 1.5 × 109/L without granulocyte colony-stimulating factor support
   * WBC count ≥ 2.5 × 109/L
   * Lymphocyte count ≥ 0.5 × 109/L
   * Platelet count ≥ 100 × 109/L without transfusion
   * Hemoglobin ≥ 9 g/dL without transfusion
   * Serum albumin ≥ 2.5 g/dL
   * Total bilirubin ≤ 1.5 × ULN
   * AST and ALT ≤ 2.0 x ULN
   * Amylase and lipase ≤ 1.5 x ULN
   * ALP ≤ 2.5 × ULN or, for patients with documented liver or bone metastases, ALP ≤ 5 × ULN
   * Serum creatinine ≤ 1.5 × ULN or CrCl ≥ 40mL/min on the basis of measured CrCl from a 24-hour urine collection or Crockcroft-Gault glomerular filtration rate estimation:
   * CrCL= ((140-age) x (weight in kg) x (72 x (serum creatinine in mg/dL)-1) (x 0.85 if female)
   * For patients not receiving therapeutic anticoagulation: INR or aPTT ≤ 1.5 × ULN within 28 days prior to initiation of study treatment
   * For patients receiving therapeutic anticoagulation: stable anticoagulant regi-men and stable INR during the 28 days immediately preceding initiation of study treatment
9. For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures, and agreement to refrain from donating sperm, as defined below:

   1. With female partners of childbearing potential, men must remain abstinent or use a condom plus an additional contraceptive method that together result in a failure rate of \< 1% per year during the treatment period and for at least 6 months after the last dose of study treatment. Men must refrain from donating sperm during this same period.
   2. With pregnant female partners, men must remain abstinent or use a condom during the treatment period and for 6 months after the last dose of study treatment to avoid exposing the embryo.
   3. The reliability of sexual abstinence should be evaluated in relation to the dura-tion of the clinical trial and the preferred and usual lifestyle of the patient. Periodic abstinence and withdrawal are not acceptable methods of contraception
10. For WOCBP: agreement to remain abstinent (refrain from heterosexual inter-course) or use a contraceptive method with a failure rate of \<1% per year during the treatment period and for 6 months after the last dose of study treatment

    1. A woman is considered to be of childbearing potential if she is postmenarcheal, has not reached a postmenopausal state, and has not undergone surgical sterilization
    2. Examples of contraceptive methods with a failure rate of \< 1% per year include bilateral tubal ligation, male sterilization, hormonal contraceptives that inhibit ovulation, hormone-releasing intrauterine devices (IUD), and copper IUDs.
    3. Hormonal contraceptive methods must be supplemented by a barrier method. The reliability of sexual abstinence should be evaluated in relation to the duration of the clinical trial and the preferred and usual lifestyle of the patient. Periodic abstinence and withdrawal are not acceptable methods of contraception.
11. Female subjects who are lactating have to discontinue nursing prior to the first dose of study drug and must refrain from nursing throughout the treatment period and for 14 days following the last dose of study drug.

Exclusion Criteria:

1. Candidates for direct surgery: patients with single site easily resectable metasta-sis
2. Major surgical procedure or significant traumatic injury within 2 weeks prior to first dose of study drug treatment
3. Palliative radiotherapy within 14 days prior to initiation of study treatment
4. Active malignancy (other than BRAFV600 mutation-positive melanoma) or malig-nancy within 3 years prior to screening are excluded, with the exception of resected melanoma, resected BCC, resected cuSCC, resected carcinoma in situ of the cervix, resected carcinoma in situ of the breast, in situ prostate cancer, limited-stage bladder cancer, or any other curatively treated malignancies from which the patient has been disease-free for at least 3 years

   a. Patients with a history of isolated elevation in prostate-specific antigen in the absence of radiographic evidence of metastatic prostate cancer are eligible for the study.
5. A history of or evidence of retinal pathology on ophthalmologic examination that is considered a risk factor for neurosensory retinal detachment, CSCR, RVO, or ne-ovascular macular degeneration

   a. Patients will be excluded from study participation if they currently are known to have any of the following risk factors for RVO: i. History of serous retinopathy ii. History of RVO iii. Evidence of ongoing serous retinopathy or RVO at baseline
6. History of clinically significant cardiac dysfunction, including the following:

   1. Poorly controlled hypertension, defined as sustained, uncontrolled, non-episodic baseline hypertension consistently above 159/99mmHg despite opti-mal medical management
   2. Unstable angina, or new-onset angina within 3 months prior to initiation of study treatment
   3. Symptomatic congestive heart failure, defined as NYHA Class II or higher
   4. Myocardial infarction within 3 months prior to initiation of study treatment
   5. Unstable arrhythmia
   6. History of congenital long QT syndrome
   7. QTcF ≥480 ms at screening, or uncorrectable abnormalities in serum electro-lytes
   8. LVEF below the institutional lower limit of normal or below 50%, whichever is lower
7. Untreated or actively progressing CNS lesions (carcinomatous meningitis)
8. Patients with a history of CNS lesions are eligible, provided that all of the following criteria are met:

   1. Measurable disease, per RECIST v1.1, must be present outside the CNS
   2. All known CNS lesions have been treated with radiotherapy or surgery
   3. CNS lesions have not been treated with whole-brain radiotherapy, except in patients who underwent definitive resection of or stereotactic therapy for all radiologically detectable parenchymal brain lesions
   4. Absence of interim progression must be confirmed by radiographic study within 4 weeks prior to initiation of study treatment. If new CNS metastases are suspected during the screening period, a confirmatory radiographic study is required prior to initiation of study treatment
   5. Any radiotherapy or surgery must be completed ≥ 4 weeks prior to initiation of study treatment
   6. There is no ongoing requirement for corticosteroids, and any prior corticosteroid treatment must be discontinued ≥ 2 weeks prior to initiation of study treatment. Treatment with an anticonvulsant at a stable dose is allowed
   7. No history of intracranial hemorrhage from CNS lesions
9. History of metastases to brain stem, midbrain, pons, or medulla, or within 10 mm of the optic apparatus
10. History of leptomeningeal metastatic disease
11. Anticipated use of any concomitant medication during or within 7 days prior to initiation of study treatment that is known to cause QT prolongation. Patients with regular amiodaron intake in the last 365 days cannot be included.
12. Uncontrolled diabetes or symptomatic hyperglycemia
13. History of malabsorption or other clinically significant metabolic dysfunction that may interfere with absorption of oral study treatment
14. Pregnancy or lactation period or intention to become pregnant during the study.

    a. WOCBP must have a negative serum pregnancy test result within 7 days prior to initiation of study treatment
15. Prior allogeneic stem cell or solid organ transplantation
16. History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced pneumonitis, or idiopathic pneumonitis, or evidence of active pneumonitis on screening chest CT scan

    a. History of radiation pneumonitis in the radiation field (fibrosis) is permitted.
17. Active or history of autoimmune disease or immune deficiency, including, but not limited to, myasthenia gravis, myositis, autoimmune hepatitis, systemic lupus ery-thematosus, rheumatoid arthritis, inflammatory bowel disease, antiphospholipid antibody syndrome, Wegener granulomatosis, Sjögren syndrome, Guillain-Barré syndrome, or multiple sclerosis, with the following exceptions:

    a. Patients with a history of autoimmune-related hypothyroidism on a stable dose of thyroid-replacement hormone may be eligible for the study after discussion with and approval by the Medical Monitor b. Patients with controlled Type 1 diabetes mellitus on a stable insulin regimen may be eligible for the study after discussion with and approval by the Medical Monitor c. Patients with eczema, psoriasis, lichen simplex chronicus, or vitiligo with der-matologic manifestations only are eligible for the study provided all of following conditions are met: i. Rash must cover \< 10% of body surface area ii. Disease is well controlled at baseline and requires only low-potency topical corticosteroids iii. No occurrence of acute exacerbations of the underlying condition requiring psoralen plus ultraviolet A radiation, methotrexate, retinoids, biologic agents, oral calcineurin inhibitors, or high-potency or oral cor-ticosteroids within the previous 12 months
18. Known clinically significant liver disease, including alcoholism, cirrhosis, fatty liver, and other inherited liver disease as well as active viral disease including:

    1. Positive HIV test at screening
    2. Active HBV infection, defined as having a positive HBsAg test at screening Patients with a past or resolved HBV infection, defined as having a negative HBsAg test and a positive total HBcAb test at screening, are eligible for the study
    3. Active HCV infection, defined as having a positive HCV antibody test and a positive HCV RNA test at screening
19. Active tuberculosis
20. Severe infection within 4 weeks prior to initiation of study treatment, including, but not limited to, hospitalization for complications of infection, bacteremia, or severe pneumonia
21. Any Grade ≥ 3 hemorrhage or bleeding event within 4 weeks prior to initiation of study treatment
22. History of stroke, reversible ischemic neurological defect, or transient ischemic at-tack within 6 months prior to initiation of study treatment
23. Current severe, uncontrolled systemic disease or any other disease, metabolic dysfunction, physical examination finding, or clinical laboratory finding that contraindicates the use of an investigational drug, may affect the interpretation of the results, or could jeopardize the safety of the patient and their compliance in the study
24. Signs or symptoms of clinically relevant infection and/or treatment with therapeutic systemic antibiotics within 2 weeks prior to initiation of study treatment

    a. Patients receiving prophylactic antibiotics are eligible for the study
25. Treatment with a live, attenuated vaccine within 4 weeks prior to initiation of study treatment, or anticipation of need for such a vaccine during the course of the study
26. Treatment with systemic immunosuppressive medication within 2 weeks prior to initiation of study treatment, or anticipation of need for systemic immunosuppressive medication during the study

    1. Patients who have received acute, low-dose systemic immunosuppressant medication ≥ 4 weeks prior to ini-tiation of study treatment or a one-time pulse dose of systemic immunosup-pressant medication are eligible for the study.
    2. The use of inhaled corticosteroids for chronic obstructive pulmonary disease or asthma, mineralocorticoids , or low-dose corticosteroids for patients with orthostatic hypotension or adrenocortical insufficiency is allowed.
27. Known hypersensitivity to biopharmaceutical agents produced in Chinese hamster ovary cells
28. Known hypersensitivity to any component of the atezo, cobi, or vem formulations
29. History of severe allergic, anaphylactic or other hypersensitivity reactions to chi-meric or humanized antibodies or fusion proteins
30. Treatment with any other investigational agent or participation in another clinical study with therapeutic intent within 4 weeks of the start of study treatment.
31. Inability or unwillingness to swallow pills
32. Any psychological, familial, sociological, or geographical conditions that may hamper compliance with the protocol and follow-up after treatment discontinuation
33. Requirement for concomitant therapy or food that is prohibited during the study, as described in Sections 10.10 and 10.11.
34. Patient is unable to comply with the study protocol for any other reason
B: Inclusion Criteria:

* Age ≥18 years
* Histologically confirmed AJCC Stage IIIB or IIIC (Tx, T1-4, N1b, N2b, N2c, N3, Mo) cutaneous melanoma or unknown primary determined to be BRAF V600 mutation positive, with sufficient nodal or in-transit disease to enable biopsies prior to surgery.Patients must have disease that is measurable per RECIST version 1.1
* Able to swallow and retain oral medication and must not have any clinically significant gastrointestinal abnormalities that may alter absorption
* Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-1
* Adequate baseline organ function
* Women of childbearing potential must have a negative serum pregnancy test within 7 days of first dose of study treatment and agree to use effective contraception from 14 days prior to commencing study treatment, throughout the treatment period and for 4 months after the last dose of study treatment
* Men with any female partner of childbearing potential must agree to use effective contraception from 14 days prior to commencing study treatment, throughout the treatment period and for 4 months after the last dose of study treatment

Exclusion Criteria:

* Known mucosal or ocular melanoma or any unresectable in-transit metastases
* Evidence of distant metastatic disease on screening evaluation
* Prior anti-cancer treatment for melanoma (chemotherapy, immunotherapy, biologic therapy, vaccine therapy, investigational treatment or radiotherapy). Prior surgery for melanoma is allowed.
* Taken an investigational drug within 28 days or 5 half-lives, whichever is longer, prior to commencing study treatment.
* Current or expected use of a prohibited medication(s)
* Known immediate or delayed hypersensitivity reaction or idiosyncrasy to drugs chemically related to the study treatments, their excipients, and/or dimethyl sulfoxide (DMSO)
* Known HIV
* A history of known glucose-6-phosphate dehydrogenase (G6PD) deficiency
* History of another malignancy or a concurrent malignancy except:

  1. Patients who have been disease-free for 3 years and have a life expectancy of \> 5 years;
  2. Patients with a history of completely resected non-melanoma skin cancer or successfully treated in situ carcinoma are eligible, for example cervical cancer in situ, atypical melanocytic hyperplasia or melanoma in situ, multiple primary melanomas.
* A history or evidence of cardiovascular risk including any of the following: a. QT interval corrected for heart rate using the Bazett's formula ≥480 msec or ≥ 450 msec for patients with bundle branch block; b. History or evidence of current clinically significant uncontrolled arrhythmias; c. History of acute coronary syndromes (including myocardial infarction or unstable angina), coronary angioplasty, or stenting within 6 months prior to commencement of study treatment; d. History or evidence of current ≥ Class II congestive heart failure; e. Abnormal cardiac valve morphology documented by echocardiogram which in the opinion of the investigator could interfere with the patient's safety.

  f. Treatment refractory hypertension defined as a blood pressure of systolic \> 140 mm Hg and/or diastolic \> 90 mm Hg which cannot be controlled by anti-hypertensive therapy.
* A history or current evidence/risk of retinal vein occlusion (RVO) or central serous retinopathy (CSR)
* Any serious or unstable pre-existing medical conditions (aside from the malignancy exceptions specified above), psychiatric disorders, or other conditions that, in the opinion of the treating clinician, could interfere with the patient's safety, obtaining informed consent, or compliance with study procedures.
* Breastfeeding females
C: Inclusion Criteria:

* Participants with histologically confirmed melanoma, either unresectable stage IIIc or stage IV metastatic melanoma, as defined by the American Joint Committee on Cancer 7th edition. Unresectability of stage IIIc disease must have confirmation from a surgical oncologist
* Participants must be naïve to treatment for locally advanced unresectable or metastatic disease (ie, no prior systemic anti-cancer therapy for advanced disease; stage IIIc and IV). Prior adjuvant immunotherapy (including ipilimumab) is allowed
* Documentation of BRAF V600 mutation-positive status in melanoma tumor tissue (archival or newly obtained tumor samples) using the cobas 4800 BRAF V600 mutation test
* Measurable disease per RECIST v1.1
* Eastern Clinical Oncology Group performance status of 0 or 1
* Consent to provide archival for biomarker analyses
* Consent to undergo tumor biopsies for biomarker analyses
* Life expectancy greater than or equal to (≥) 12 weeks
* Adequate hematologic and end organ function

Exclusion Criteria:

* History of prior rapidly accelerated fibrosarcoma or mitogen-activated protein kinase pathway inhibitor treatment
* Palliative radiotherapy within 14 days prior to the first dose of study treatment
* Major surgery or traumatic injury within 14 days prior to first dose of study treatment
* Active malignancy other than melanoma that could potentially interfere with the interpretation of efficacy measures. Participants with a previous malignancy within the past 3 years are excluded except for participants with resected basal cell carcinoma or squamous cell carcinoma of the skin, melanoma in-situ, carcinoma in-situ of the cervix, and carcinoma in-situ of the breast
* History of or evidence of retinal pathology on ophthalmological examination that is considered a risk factor for neurosensory retinal detachment, retinal vein occlusion, or neovascular macular degeneration
* Uncontrolled glaucoma with intraocular pressure
* Serum cholesterol ≥ Grade 2
* Hypertriglyceridemia ≥ Grade 2
* Hyperglycemia (fasting) ≥ Grade 2
* History of clinically significant cardiac dysfunction
* Participants with active central nervous system (CNS) lesions (including carcinomatous meningitis) are excluded. However, participants are eligible if:

  1. All known CNS lesions have been treated with stereotactic therapy or surgery, AND
  2. There has been no evidence of clinical and radiographic disease progression in the CNS for ≥ 3 weeks after radiotherapy or surgery
* Current severe, uncontrolled systemic disease
* History of malabsorption or other condition that would interfere with absorption of study drugs
* Pregnant, lactating, or breast feeding women
D: Inclusion Criteria:

* STEP 1 REGISTRATION (RANDOMIZATION): Patients must have clinically detectable stage III (clinically detectable N1b, N1c, N2b, N2c, N3b and N3c) or stage IV resectable melanoma. Patients with melanoma of mucosal or acral origin are eligible. Patients with melanoma of uveal origin are not eligible. Patients with a history of brain metastases are not eligible. Clinically detectable is defined as disease that is apparent and measurable via physical examination or radiographic imaging.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients are eligible for this trial either at initial presentation of their melanoma or at the time of the first detected nodal, satellite/in-transit, distant metastases, or recurrent disease in prior lymphadenectomy basin or distant site. Nodal, satellite/in-transit metastasis, distant metastases or disease in a prior complete lymphadenectomy basin must have been confirmed histologically by hematoxylin (H) \& eosin (E) stained slides.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients with multiple regional nodal basin involvement are eligible. Gross or microscopic extracapsular nodal extension is permitted.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must have histologically proven stage IIIB or higher. This would entail pathologic confirmation beyond the primary or initial diagnosis of melanoma involving fine needle aspiration cytology or biopsy confirmation of any N-category or M-category resectable site.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must not have received previous neoadjuvant treatment for their melanoma. Patients may have received prior non-immunotherapy adjuvant therapy. Patients must not have had prior immunotherapy including, but not limited to ipilimumab, interferon alfa-2b, high dose interleukin (IL)-2, pegylated-interferon (PEG-IFN), anti-PD-1, anti-PD-L1 intra-tumoral, or vaccine therapies. Patients must not be planning to receive any of the prohibited therapies during treatment phases on the study.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must not be planning to receive concomitant other biologic therapy, hormonal therapy, other chemotherapy, surgery, while on protocol therapy.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients may have received prior radiation therapy, including after prior surgical resection. All adverse events associated with prior surgery and radiation therapy must have resolved to =\< grade 1 prior to randomization.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must be \>= 18 years of age
* STEP 1 REGISTRATION (RANDOMIZATION): All patients must have disease status documented by a complete physical examination and imaging studies within 42 days prior to randomization. Imaging studies must include a CT of the chest, abdomen and pelvis with intravenous contrast (unless contraindicated). For patients with melanoma arising from the head and neck, dedicated neck imaging (CT with intravenous contrast is required. If the patient has unknown primary with disease in the axilla, neck imaging is required CT imaging must be done with intravenous contrast if there are no contraindications for it. Extremity melanomas must be imaged using CT with intravenous contrast or MRI with and without gadolinium

  * Note: PET-CT scans are NOT acceptable to establish eligibility. Non-iodinated CT scans that are part of common PET-CT imaging protocols do not provide contrast for difficult to ascertain areas such as the neck and liver, and do not provide enough CT detail to perform appropriate RECIST 1.1 measurements. As such, a PET-CT with non-contrast CT or non-diagnostic quality CT images is considered insufficient for the detection of melanoma.
* STEP 1 REGISTRATION (RANDOMIZATION): All patients must have a CT or magnetic resonance imaging (MRI) of the brain within 42 days prior to randomization. The brain CT or MRI should be performed with intravenous contrast (unless contraindicated).
* STEP 1 REGISTRATION (RANDOMIZATION): Absolute neutrophil count (ANC) \>= 1,500/microliter (mcL) (within 42 days prior to randomization).
* STEP 1 REGISTRATION (RANDOMIZATION): Platelets \>= 100,000/mcL (within 42 days prior to randomization).
* STEP 1 REGISTRATION (RANDOMIZATION): Hemoglobin \>= 10 g/dL (within 42 days prior to randomization).
* STEP 1 REGISTRATION (RANDOMIZATION): Total bilirubin =\< 1.5 x institutional upper limit of normal (IULN) (except patients with Gilbert's syndrome, who must have a total bilirubin \< 3.0 mg/dL) (within 42 days prior to randomization).
* STEP 1 REGISTRATION (RANDOMIZATION): Serum glutamic-oxaloacetic transaminase (SGOT) (aspartate aminotransferase \[AST\]) and serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase \[ALT\]) =\< 2 x IULN (within 42 days prior to randomization).
* STEP 1 REGISTRATION (RANDOMIZATION): Alkaline phosphatase =\< 2 x IULN (within 42 days prior to randomization).
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must have lactate dehydrogenase (LDH) performed within 42 days prior to randomization.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must have adequate renal function as evidenced by calculated creatinine clearance \> 30 mL/min. The creatinine level (mg/dL) used in the calculation must be obtained within 42 days prior to randomization.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must have Zubrod performance status =\< 2.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must not have a history of (non-infectious) pneumonitis that required steroids or current pneumonitis.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must not have an active infection requiring systemic therapy.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must not have active autoimmune disease that has required systemic treatment in past 2 years (i.e., with use of disease modifying agents, corticosteroids 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.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must not have received live vaccines within 42 days prior to randomization. Examples of live vaccines include, but are not limited to, the following: measles, mumps, rubella, chicken pox, shingles, yellow fever, rabies, Bacillus Calmette-Guerin (BCG), and typhoid (oral) vaccine. Seasonal influenza vaccines for injection are generally killed virus vaccines and are allowed; however, intranasal influenza vaccines (e.g., Flu-Mist) are live attenuated vaccines, and are not allowed.

  * NOTE: The COVID-19 vaccines (currently available and those in the pipeline for FDA emergency use authorization or FDA approval) do not contain live virus, and therefore, COVID-19 vaccination does not affect or preclude eligibility for the S1801 trial. For patients who have undergone lymphadenectomy, vaccines should be delivered to a limb with an intact lymph node basin (Sentinel lymph node biopsy in a limb is acceptable). The vaccine should not be administered in a limb that has undergone lymphadenectomy.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients known to be human immunodeficiency virus (HIV) positive are eligible if they meet the following criteria within 30 days prior to randomization: stable and adequate CD4 counts (\>= 350 mm\^3), and serum HIV viral load of \< 25,000 IU/ml. Patients may be on or off anti-viral therapy so long as they meet the CD4 count criteria.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must not have known active hepatitis B virus (HBV) or hepatitis C virus (HCV) infection prior to randomization. Note: No testing for hepatitis B and hepatitis C is required unless mandated by local health authority.
* STEP 1 REGISTRATION (RANDOMIZATION): Prior malignancy is allowed providing it does not require concurrent therapy.
* STEP 1 REGISTRATION (RANDOMIZATION): Women of childbearing potential must have a negative urine or serum pregnancy test within 28 days prior to randomization. Women/men of reproductive potential must have agreed to use an effective contraceptive method for the course of the study through 120 days after the last dose of study medication. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately. A woman is considered to be of "reproductive potential" if she has had menses at any time in the preceding 12 consecutive months. In addition to routine contraceptive methods, "effective contraception" also includes heterosexual celibacy and surgery intended to prevent pregnancy (or with a side-effect of pregnancy prevention) defined as a hysterectomy, bilateral oophorectomy, or bilateral tubal ligation. However, if at any point a previously celibate patient chooses to become heterosexually active during the time period for use of contraceptive measures outlined in the protocol, he/she is responsible for beginning contraceptive measures. Patients must not be pregnant or nursing due to unknown teratogenic side effects.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must be deemed medically fit to undergo surgery by the treating medical/surgical team.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must be willing to submit the following surgical specimens: either all tissue blocks from the surgical specimen or two slides per block (\[1\] hematoxylin and eosin \[H\&E\] slide and \[1\] unstained slide OR \[2\] unstained slides if H\&E stained slides cannot be provided).
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must be offered the opportunity to participate in specimen banking.
* STEP 1 REGISTRATION (RANDOMIZATION): Patients must be informed of the investigational nature of this study and must sign and give written informed consent for this protocol in accordance with institutional and federal guidelines.
* STEP 1 REGISTRATION (RANDOMIZATION): As a part of the Oncology Patient Enrollment Network (OPEN) randomization process the treating institution's identity is provided in order to ensure that the current (within 365 days) date of institutional review board approval for this study has been entered in the system.
* STEP 2 REGISTRATION (SURGERY): Patients randomized to arm 2 (neoadjuvant arm) must be willing to submit tissue to determine pathologic response regardless of number of pre-operative doses of pembrolizumab (MK-3475) received. Determination of pathologic response cannot be done on less than the full surgical specimen.
* STEP 2 REGISTRATION (SURGERY): Patients must have disease assessments by CT chest/abdomen/pelvis with IV contrast, and neck CT with IV contrast if primary head and neck melanoma, performed within 42 days (and no more than 49 days) before the planned date of surgery. MRI combined with non-contrast CT is an acceptable alternative for patients with CT contrast allergy, but imaging must encompass total body.
* STEP 2 REGISTRATION (SURGERY): Patients must register to step 2 within 17 days prior to planned date of surgery.
* STEP 3 REGISTRATION (ADJUVANT THERAPY): Patients must have undergone surgery prior to Step 3 registration. The Step 2 surgery must have completely resected their melanoma.

  * Patients with gross positive residual disease following surgery do not qualify as having disease-free status, and, therefore, such patients are not eligible to register for adjuvant therapy.
  * Patients with microscopic residual disease (i.e., positive margins) can be treated with re-excision or radiation, per site discretion, to render the patient disease-free prior to registration of adjuvant therapy.
  * Disease-free status must be documented by a complete physical examination and radiographic imaging studies within 42 days prior to Step 3 registration. Imaging studies must include a CT of the chest, abdomen, and pelvis (unless contraindicated). Extremity melanomas must be imaged using CT with intravenous contrast or MRI with and without gadolinium. CT imaging must be done with intravenous contrast if there are no contraindications for it.
  * For patients with melanoma arising from the head and neck, dedicated neck imaging (CT with IV contrast, unless contraindicated) is required.
  * If the patient has had unknown primary with disease in the axilla, neck imaging is required to assure the region is clear of cancer.
  * Any other clinically indicated imaging studies if performed (e.g., bone scan) must show no evidence of disease.
* STEP 3 REGISTRATION (ADJUVANT THERAPY): Patients must be registered to step 3 no more than 84 days after date of surgery.
* STEP 3 REGISTRATION (ADJUVANT THERAPY): Patients with R0 or R1 resections must have disease-free status documented by a complete physical examination and imaging studies within 42 days prior to step 3 registration. These patients must have disease assessments by CT chest/abdomen/pelvis with IV contrast, and neck CT with IV contrast if primary head and neck melanoma. MRI combined with non-contrast CT is an acceptable alternative for patients with CT contrast allergy, but imaging must encompass total body.
* STEP 3 REGISTRATION (ADJUVANT THERAPY): Patients with R2 resections are not eligible for step 3 and must be removed from study treatment

Answer: D