AB821 in Adult Participants With Locally Advanced or Metastatic Solid Tumors

This is an early-phase study testing a new investigational drug called AB821 in adults with advanced or metastatic solid tumors (cancers that have spread and cannot be surgically removed). **You may be eligible if:** - You are 18 or older - You have an advanced or metastatic solid tumor - Your cancer has progressed despite available standard treatments - You are in good physical health (able to perform most daily activities) - Your blood counts, kidney, and liver function are within acceptable ranges - You are willing to use contraception if applicable **You may NOT be eligible if:** - You have active brain metastases (cancer spread to the brain) that are unstable - You have a serious active infection or immune system disorder - You are pregnant or breastfeeding - Your organ function (kidney, liver, blood) is significantly impaired - You have had certain prior treatments that would interfere with this drug Talk to your doctor to see if this trial is right for you.