Study of CM-24 (MK-6018) Alone and In Combination With Pembrolizumab (MK-3475) in Participants With Selected Advanced or Recurrent Malignancies (MK-6018-001)

Inclusion Criteria: * Males and females ≥18 years of age * Participants in the Dose Escalation portion must have one of the following advanced or recurrent malignancies: gastrointestinal (colorectal or gastric); ovarian; melanoma; non-small cell lung adenocarcinoma; or bladder. * Participants in the Monotherapy Expansion Cohort must have one of the following advanced or recurrent malignancies: cutaneous melanoma showing primary progression following treatment with an anti-programmed cell death (PD) or anti-PDL1 regimen; or anti-PD1 or anti-PD-L1 treatment-naïve colorectal or gastric cancer, including gastroesophageal junction cancer of Siewert Type II and Type III. * Participants in the Combination Expansion Cohorts must have one of the following advanced or recurrent malignancies: non-small cell lung adenocarcinoma or cutaneous melanoma showing primary progression following treatment with an anti-PD1 or anti-PD-L1 regimen; or anti-PD1 or anti-PD-L1 treatment-naïve colorectal or gastric cancer, including gastroesophageal junction cancer of Siewert Type II and Type III. * Melanoma with BRAF V600E or V600K mutation-positive melanoma must have progressed on, or were intolerant to, prior BRAF- or MEK-inhibitor therapy * Must have at least 1 measurable lesion per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 with progressing or new tumors since last antitumor therapy * Must have adequate hematologic, renal, and liver function * Eastern Cooperative Oncology Group (ECOG) performance status 0-1 * Females must not be pregnant (negative human chorionic gonadotropin test within 72 hours prior to receiving the first dose of study medication) or breastfeeding * Women of childbearing potential and male participants must agree to use adequate contraception throughout the study and for up to 180 days after study treatment * An estimated life expectancy of at least 3 months * Must consent to provide an archival tumor biopsy sample at any time point from screening to study exit * Must consent to allow the acquisition of new tissue biopsy samples during the study Exclusion Criteria: * History of severe hypersensitivity reactions or immune related adverse events to other monoclonal antibodies * History of other active malignancy within the prior 2 years * History of insulin-dependent or uncontrolled Diabetes Mellitus * History of inflammatory bowel disease * Autoimmune disorders * Known HIV and/or Hepatitis B or C infections * Known systemic bleeding or platelet disorder * Receipt of live vaccines with 4 weeks (28 days) of study * History or evidence of non-infectious pneumonitis that required steroids or current pneumonitis