A Phase 1 Study of PLN-101095 in Adults With Advanced or Metastatic Solid Tumors

This is a Phase 1a/1b, dose-escalation/expansion, consecutive-cohort, open-label study to evaluate the safety, tolerability, PK, PD, and preliminary evidence of antitumor activity of PLN-101095 in combination with pembrolizumab (the study treatment regimen) in adult participants with advanced or metastatic solid tumors for which pembrolizumab is indicated but have documented disease progression (refractory \[primary resistance\]) or relapsed \[secondary resistance\]) after at least 3 months from the start of treatment with pembrolizumab. The study will consist of 2 main parts: * Part 1: Consecutive dose-escalation cohorts using a Bayesian optimal interval (BOIN) dose escalation design with accelerated titration * Part 2: Dose-expansion cohorts using Simon's 2-stage design