A Study to Evaluate KIN-2787 in Participants With BRAF and/or NRAS Mutation Positive Solid Tumors

Inclusion Criteria: * Provide written informed consent prior to initiation of any study-specific procedures. * Metastatic or advanced stage solid tumor * Known BRAF Class I, Class II, or Class III alteration or melanoma with an NRAS mutation as confirmed by previous genomic analysis of tumor tissue or ctDNA. * Measurable (Part A and B) or evaluable (Part A only) disease by RECIST v1.1. * ECOG performance status 0-1 * Adequate organ function, as measured by laboratory values (criteria listed in protocol). * Able to swallow, retain, and absorb oral medications. Exclusion Criteria: * Known participants who have received local therapy with either surgery and/or radiation therapy (participants with asymptomatic untreated brain metastasis may be eligible if met with certain criteria) * In Part B Dose Expansion, previous treatment with any approved or in-development small molecule BRAF-, MEK-, or MAPK-directed inhibitor therapy. * GI tract disease causing an inability to take oral medication, malabsorption syndrome, requirement for intravenous alimentation, or uncontrolled inflammatory GI disease. * Active, uncontrolled bacterial, fungal, or viral infection. * Participant with a positive test result for SARS-CoV2 infection, is known to have asymptomatic infection or is suspected of having SARS-CoV2, is excluded * Women who are lactating or breastfeeding, or pregnant. * Participants with any other active treated malignancy within 3 years prior to enrollment Complete inclusion and exclusion criteria are listed in the clinical study protocol.