Inclusion Criteria:

          1. Adult patients ≥18 years of age.

          2. Patients with confirmed solid tumors (including urothelial carcinoma) who have locally
             recurrent or metastatic disease that has progressed on or following all standard of
             care therapies or who is not a candidate for standard treatment.

          3. For patients with urothelial carcinoma to be enrolled in the Combination Treatment
             arm, patients must have confirmation of urothelial carcinoma and have unresectable
             locally recurrent or metastatic disease that has progressed on or following all
             standard of care therapies, or who is not a candidate for standard treatment.
             Checkpoint inhibitor therapy with anti-PD-1 or anti-PD-L1 does not necessarily need to
             directly precede the study, but patients must have progressed on or within 3 months of
             receiving the last infusion/dose anti-PD-(L)1 therapy for inclusion in the Combination
             Treatment arm only.

          4. Have measurable disease.

          5. Accessible tumor that can be safely accessed for multiple core biopsies and patient is
             willing to provide tissue from newly obtain biopsies before and during treatment.

          6. Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1.

          7. Adequate organ function.

          8. Highly effective birth control.

          9. Time since the last dose of prior therapy to treat underlying malignancy (including
             other investigational therapy): 9a. Systemic cytotoxic chemotherapy: ≥ the duration of
             the most recent cycle of the previous regimen (with a minimum of 2 weeks for all,
             except 6 weeks for systemic nitrosourea or systemic mitomycin-C). 9b. Biologic therapy
             (eg, antibodies): ≥ 3 weeks or their dosing interval if shorter than 3 weeks (e.g. q2w
             therapy would require a 2-week washout). 9c. Small molecule therapies: ≥ 5 ×
             half-life. 9d. Investigational Agent: ≥4 weeks or ≥5 × half-life, whichever is shorter

        Exclusion Criteria:

          1. Untreated symptomatic central nervous system (CNS) tumors or brain metastasis.
             Patients are eligible if CNS metastases are asymptomatic and do not require immediate
             treatment or have been treated and patients have neurologically returned to baseline
             (residual signs or symptoms related to the CNS treatment are permitted). In addition,
             patients must have been either off corticosteroids, or on a stable or decreasing dose
             of ≤10 mg daily prednisone (or equivalent) for at least 2 weeks prior to entering the
             Treatment period (Day 1).

          2. Patients who have not recovered to ≤ Grade 1 or baseline from all adverse events (AEs)
             due to previous therapies

          3. Has an active autoimmune disease that has required systemic treatment in past 2 years
             with the use of disease-modifying agents, corticosteroids, or immunosuppressive drugs;
             nonsteroidal anti-inflammatory drugs (NSAIDs) are permitted. Patients with type 1
             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.

          4. Any condition requiring continuous systemic treatment with either corticosteroids
             (>10mg daily prednisone equivalents) or other immunosuppressive medications within 2
             weeks prior to first dose of study treatment (Inhaled or topical steroids and
             physiological replacement doses of up to 10 mg daily prednisone equivalent are
             permitted in the absence of active clinically significant [ie, severe] autoimmune
             disease.).

          5. Any other concurrent antineoplastic treatment or investigational agent except for
             allowed local radiation of lesions for palliation and hormone ablation.

          6. Uncontrolled or life-threatening symptomatic concomitant disease (including known
             symptomatic human immunodeficiency virus (HIV) positive with an AIDS defining
             opportunistic infection within the last year, or a current CD4 count <350 cells/uL,
             symptomatic active hepatitis B or C checked at screening, or active tuberculosis).
             Patients with HIV are eligible if: 6a. they have received antiretroviral therapy (ART)
             for at least 4 weeks prior to entering the Treatment period as clinical indicated
             while enrolled on study; 6b. they continue on ART as clinically indicated while
             enrolled on study; 6c. CD4 counts and viral load are monitored per standard of care by
             a local health care provider.

          7. Patients that have undergone a major surgery within 3 weeks of starting trial
             treatment or has inadequate healing or recovery from complications of surgery prior to
             starting trial treatment.

          8. Prior radiotherapy within 2 weeks of start of study treatment. Subjects must have
             recovered from all radiation-related toxicities, not require corticosteroids, and not
             have had severe radiation pneumonitis. A 1-week washout is permitted for palliative
             radiation [≤ 2 weeks of radiotherapy] to non-CNS disease.

          9. Prior AHR inhibitor treatment without Sponsor permission.

         10. Potentially life-threatening second malignancy requiring systemic treatment within the
             last 3 years or which would impede evaluation of treatment response. Hormone ablation
             therapy is allowed within the last 3 years. Patients with history of prior early stage
             basal/squamous cell skin cancer or non-invasive or in situ cancers that have undergone
             definitive treatment at any time are eligible.

         11. Recent or current significant cardiovascular disease (e.g. stroke, heart attack, heart
             failure, or arrhythmia).

         12. Medical issue that limits oral ingestion or impairment of gastrointestinal function
             that is expected to significantly reduce the absorption of IK-175.

         13. Clinically significant (ie, active) cardiovascular disease: cerebral vascular
             accident/stroke (<6 months prior to enrollment), myocardial infarction (<6 months
             prior to enrollment), unstable angina, congestive heart failure (≥ New York Heart
             Association Classification Class II), or the presence of any condition that can
             increase proarrhythmic risk (eg, hypokalemia, bradycardia, heart block) including any
             new, unstable, or serious cardiac arrhythmia requiring medication, or other baseline
             arrhythmia that might interfere with interpretation of ECGs on study (eg, bundle
             branch block). Patients with QTcF >450 msec for males and >470 msec for females on
             screening ECG are excluded. Any patients with a bundle branch block will be excluded
             with QTcF >450 msec. Males who are on stable doses of concomitant medication with
             known prolongation of QTcF (eg, Selective Serotonin Reuptake Inhibitor
             Antidepressants) will only be excluded for QTcF >470 msec.

         14. History of life-threatening toxicity related to prior immune therapy (eg. anti-CTLA-4
             or anti-PD-1/PD-L1 treatment or any other antibody or drug specifically targeting
             T-cell co-stimulation or immune checkpoint pathways) except those that are unlikely to
             re-occur with standard countermeasures (eg. hormone replacement after adrenal crisis).

         15. Has an active infection requiring systemic therapy.

         16. Treatment with any live/attenuated vaccine within 30 days of first study treatment.

         17. A woman of child-bearing potential (WOCBP) who has a positive pregnancy test or is
             breastfeeding prior to treatment.