Inclusion Criteria:

          -  Patients must have histologically or cytologically confirmed malignant neoplasms (not
             including hematological malignancies and brain tumors) untreated or previously treated
             requiring further treatment; patients in Arm L (pembrolizumab), Arm M (nivolumab), and
             Arms N, O, P (nivolumab and ipilimumab) that have Food and Drug Administration
             (FDA)-approved indications for nivolumab, ipilimumab, and pembrolizumab do not have to
             fail first line nivolumab, ipilimumab, or pembrolizumab, and these patients may be
             treatment naïve if they have disease where pembrolizumab or nivolumab are FDA approved
             for the first-line setting

          -  For all arms except Arm L (pembrolizumab), Arm M (nivolumab), and Arms N, O, P
             (nivolumab and ipilimumab) patients must have failed prior standard curative
             chemotherapy for their disease; subjects must have failed, be intolerant to, or be
             ineligible for any potentially curative approved treatment, irrespective of line of
             therapy

          -  Patients must have measurable disease (Response Evaluation Criteria in Solid Tumors
             [RECIST] 1.1)

          -  Eastern Cooperative Oncology Group (ECOG) performance status of 0-1

          -  The patient must be recovered from a prior major surgery; the major surgery must be
             performed at least 4 weeks prior to consent date

          -  Platelets >= 125 x 10^9/L (For Arm L pembrolizumab, Arm M nivolumab and Arms N, O, P
             [nivolumab and ipilimumab] and expansion cohorts for all arms, platelets >= 100 x
             10^9/L)

          -  Hemoglobin >= 10 g/dL (For Arm L pembrolizumab, Arm M nivolumab and Arms N, O, P
             [nivolumab and ipilimumab] and expansion cohorts for all arms, hemoglobin >= 9 g/dL)

          -  Absolute neutrophil count (ANC) >= 1.5 x 10^9/L (For Arm L pembrolizumab, Arm M
             nivolumab and Arms N, O, P [nivolumab and ipilimumab], ANC >= 1.0 x 10^9/L)

          -  Transfusions and growth factors are allowed

          -  Alanine transaminase (alanine aminotransferase [ALT]) =< 2 x upper normal limit (ULN)
             (in the expansion cohort, patients with known liver involvement may have ALT =< 5 x
             ULN); aspartate aminotransferase (AST) =< 2 x ULN (in the expansion cohort, patients
             with known liver involvement may have AST =< 5 x ULN)

          -  Alkaline phosphatase < 4 x ULN

          -  Total bilirubin =< 2 x ULN (in the expansion cohort, patients with Gilbert's syndrome
             [hereditary indirect hyperbilirubinemia] who must have a total bilirubin of =< 3 x
             ULN)

          -  Renal function defined as a calculated or measured glomerular filtration rate (GFR) >=
             30 mL/min. For patients with renal cell carcinoma (RCC), the GFR may be defined as >=
             25 mL/min

          -  The patient has recovered to grade =< 1 by the National Cancer Institute Common
             Terminology Criteria for Adverse Events, version 4.03 (NCI-CTCAE v4.03) from the
             effects of recent surgery, radiotherapy, chemotherapy, hormonal therapy, or other
             targeted therapies, with the exception of alopecia; the exceptions for such effects
             are allowed lab values of =< grade 2 specified elsewhere in these inclusion criteria

          -  Life expectancy of at least 12 weeks

          -  Able to swallow and retain oral medication

          -  Patients must give informed consent according to the rules and regulations of the
             individual participating sites

          -  Negative serum pregnancy test in women of childbearing potential within 7 days of
             first dose of treatment and patients of child-bearing potential must agree to use
             effective contraception during/after 3 months post dose; a woman of childbearing
             potential is defined as a premenopausal female capable of becoming pregnant; this
             includes women on oral, injectable or mechanical contraception; women who are single
             and women whose male sexual partners have been vasectomized or whose male sexual
             partners have received or are utilizing mechanical contraceptive devices

          -  For the Arm B (paclitaxel) expansion cohort, patients must have ovarian carcinoma,
             fallopian tube, or peritonea carcinoma

          -  For Arm C (eribulin) expansion cohort, patients must have triple negative breast
             cancer (eribulin naive)

          -  For Arm M (nivolumab) expansion phase, patients must have biopsiable disease

          -  For the Arm N (nivolumab and ipilimumab), patients must have metastatic or
             unresectable renal cell carcinoma (RCC)

          -  For the Arm O (nivolumab and ipilimumab) escalation and expansion Cohort O-1, patients
             must have metastatic or unresectable melanoma

          -  For the Arm O (nivolumab and ipilimumab) expansion Cohort O-2, patients must have
             metastatic or advanced solid tumors (non-melanoma, non-renal cell carcinoma, or non-
             non-small cell lung carcinoma)

          -  For the Arm P (nivolumab and ipilimumab), patients must have metastatic or
             unresectable non-small cell lung carcinoma (NSCLC)

        Exclusion Criteria:

          -  Evidence of complete or partial bowel obstruction

          -  Patients with primary central nervous system (CNS) tumor or CNS tumor involvement;
             however, patients with metastatic CNS tumors may participate in this study if the
             patient is:

               -  > 4 weeks from prior therapy completion (including radiation and/or surgery)

               -  Clinically stable with respect to the CNS tumor at the time of study entry

               -  Not receiving steroid therapy in treating CNS tumor or CNS tumor involvement

               -  Not receiving anti-convulsive medications (that were started for brain
                  metastases)

          -  Need of total parenteral nutrition

          -  Prior treatment with an agent targeting the exportin

          -  Allergic to selinexor or any of the chemotherapy intended to receive

          -  Pregnancy or lactation

          -  Radiation (except planned or ongoing palliative radiation to bone outside of the
             region of measurable disease) =< 3 weeks prior to study drug administration date

          -  Chemotherapy, or immunotherapy or any other systemic anticancer therapy =< 3 weeks
             prior to study drug administration date; patients receiving anti-PD-1 treatment, and
             continue to receiving this treatment in combination with selinexor (Arms L, M, N, O,
             and P), can start receiving the selinexor and anti-PD-1 combination without washout of
             the prior anti-PD-1 antibody

          -  Diagnosis or recurrence of invasive cancer other than the present cancer within 3
             years (except basal or squamous cell carcinoma of the skin that has been definitively
             treated)

          -  Major surgery within four weeks before consent date

          -  Unstable cardiovascular function: symptomatic ischemia (chest pain of cardiac origin),
             or uncontrolled clinically significant conduction abnormalities (e.g. ventricular
             tachycardia on antiarrhythmics are excluded and 1st degree atrioventricular [AV] block
             or asymptomatic left anterior fascicular block [LAFB]/right bundle branch block [RBBB]
             will not be excluded), or congestive heart failure (CHF) of New York Heart Association
             (NYHA) class >= 3, or myocardial infarction (MI) within 3 months of consent date

          -  Uncontrolled active infection requiring parenteral antibiotics, antivirals, or
             antifungals within one week prior to the first dose; active infection with concurrent
             treatment is acceptable only if the patient is clinically stable

          -  Significantly diseased (as determined by the principal investigator [PI] or treating
             physician) or obstructed gastrointestinal tract or uncontrolled vomiting or diarrhea

          -  Treatment with an investigational anti-cancer study drug within 3 weeks prior to study
             drug administration date

          -  Concurrent therapy with approved or investigational anticancer therapeutics

          -  Medical, psychological or social conditions that may interfere with the patient's
             participation in the study or evaluation of the study results

          -  Men whose partner is a woman of child-bearing potential, (i.e. biologically able to
             conceive), and who is not employing two forms of highly effective contraception;
             highly effective contraception (e.g. male condom with spermicide, diaphragm with
             spermicide, intra-uterine device) must be used by both sexes during the study and must
             be continued for 3 months after the end of study treatment; women of child-bearing
             potential is defined as sexually mature women who are not surgically sterile or who
             have not been naturally postmenopausal for at least 12 consecutive months (e.g., who
             has had menses any time in the preceding 12 consecutive months)

          -  For Arms L (pembrolizumab) and M (nivolumab), and Arms N, O, P (nivolumab and
             ipilimumab), subjects with an active, known or suspected autoimmune disease; subjects
             with type I diabetes mellitus, hypothyroidism only requiring hormone replacement, skin
             disorders (such as vitiligo, psoriasis, or alopecia) not requiring systemic treatment,
             or conditions not expected to recur in the absence of an external trigger are
             permitted to enroll

          -  For Arms L (pembrolizumab) and M (nivolumab), and Arms N, O, P (nivolumab and
             ipilimumab), subjects receiving chronic systemic steroid therapy (in dosing exceeding
             10 mg daily of prednisone equivalent) or other form of immunosuppressive therapy
             within 7 days before the first dose of study treatment; use of inhaled or topical
             steroids or systemic corticosteroids =< 10 mg is permitted; in addition, physiologic
             steroid replacement with hydrocortisone is allowed

          -  For Arms L (pembrolizumab) and M (nivolumab), and Arms N, O, P (nivolumab and
             ipilimumab), history of a prior grade 3 or 4 immune-related adverse event (irAE) or
             any grade ocular irAE from prior immunotherapy

          -  For the Arm O (nivolumab and ipilimumab) expansion Cohort O-2, patients must not have
             melanoma, RCC, or NSCLC